I found the passage which troubled the inquirer:
"Ancient religions - of which those of Egypt are generally acknowledged the eldest - either exalted or feared this self-consciousness. Those which exalted it took the position that the human psyche is capable of opposition to and domination of the forces of nature. Those fearing it warned man that such a presumption of independence would be sinful and dangerous. Therefore, they said, such “will to power” should be concealed, sublimated - and if necessary punished and exterminated - that mankind might return to an Eden-like “state of nature” untroubled by the burdens of having to take responsibility for decisions, judgments, and actions based upon an essentially personal determination of “good” and “evil”. The psyche-worshipping religions were more intellectually demanding than their nature-worshipping counterparts, since it is more difficult to reason a path through one’s span of conscious existence than it is to be swept along by a current of semi-rational stimulus and response"
http://www.xeper.org/pub/gil/xp_FS_gil.htm

So what does the author mean by 'opposition to and domination of the forces of nature'? Does it mean Setians have no appreciation of 'nature' or cannot enjoy a rural 'back to Nature' lifestyle?

I do not see the Temple's philosophy as being isolated from 'Nature'. Many Temple members are members of the 'Arkte' element, which is concerned with our kinship to animals, that a part of Set's gift (the gift of consciousness) went to them. They have a sentience all their own. Some, out of understanding animals' consciousness as having some similarities with our own, have chosen a vegetarian lifestyle. (I am one who has, after an epiphany with a pig. I saw the pig napping in a pen at the Yuma County Fair. He had such a big grin on his face, he was enjoying his nap as much as I do. After that, I could no longer eat meat.) Arkte warriors fight for the cause of animals in whatever way they can, working to eliminate abuse of them. So certainly enjoying our animal companions is part of this.

I smile as you ask if one can be a Setian and "still enjoy being around plants, flowers, wild animals, and all that..." For where did I go on my recent vacation, but to enjoy the wonders of nature! After twenty one years living in Arizona, I finally saw the Grand Canyon. I enjoyed the diverse flora and fauna of northern Arizona greatly.

The following is my own raw understanding. I understand the realm of Horus to be more that of the community. I see the realm of Set as that 'which is apart'. In ancient understandings, Set never lost his rule of the deserts. This quote is from _Seth, God of Confusion_ by TeVelde:

"In the temple of Deir el Hagar in the oasis of Dakhle, Vespasian offers flowers to Seth and Nephthys. 3) As far as we know, the depiction of Seth in such a positive role in a Roman temple, after the commencement of our era, is unique. That this unique instance is found outside Egypt proper, is no accident. The desert with its oases, and more generally the foreign country that surrounds the home country and merges into chaos, is the territory where Seth is at home. It is not inconceivable that Egyptian priests who had long ceased to worship Seth in Egypt, had no objection to his adoration in more distant parts. He who is in the area where a god has power, must find a modus vivendi." (Page 116)

The desert has a unique aspect for those who can appreciate it.

"'Pastoral life, solitude, and pure time facilitate the revelation that, as we know, is produced in the desert,'write Josy Eisenberg and Armand Abecassis." (from _On Being Pagan_ by Alain de Benoist, page 150)

The desert is not as 'dead or inanimate' as some might think.

I think of that old song by the group "America":
"...I've been through the desert on a horse with no name
It felt good to be out of the rain
In the desert you can remember your name
cause there ain't no one for to give you no pain..."

In the remote regions, away from the distractions of the cities, our focus turns inward. As Set represents 'rulership in the inner world', we withdraw to our inner world, and our higher self to find the font of divinity within. Now back to that 'general information letter' at xeper.org, where you might be getting this 'anti-nature' idea. What does the author mean by 'opposition to and domination of the forces of nature'?

It's funny, I do a search for 'forces of nature' and come to the National Geographic site, which lists 'volcanos, hurricanes, earthquakes and tornados' as representing the 'forces of nature'. Oddly, as Set later became associated with the Greek Typhoon, seen as 'Set-Typhoon', just such 'force' was seen to be of his nature.

Hmmmm, next I do a search for 'state of nature', where I find it defined
State of Nature - The "natural condition of mankind" is what would exist if there were no government, no civilization, no laws, and no common power to restrain human nature. The state of nature is a "war of all against all," in which human beings constantly seek to destroy each other in an incessant pursuit for power. Life in the state of nature is "nasty, brutish and short."

I'm turning up a wild diversity of meanings. Hmmm, 'nature-worship' at Wiki leads to this:
"Earth religion is a New Age term used mostly in the context of Neopaganism. It is an umbrella phrase that is used to cover any religion that worships the Earth, Nature, or fertility gods and goddesses, such as the various forms of goddess worship. Some find a connection between Earth-worship and the Gaia hypothesis. It's in theory the opposite of UFO religion."

Umm, this is getting very complicated! 'UFO religion', I've heard of only one of those, whose adherants consider themselves a sort of 'scientist'. Hmmm. Setianism isn't a 'UFO religion'. So just what DID the author of that passage that so troubles you have in mind?

Perhaps it something similar to what Evola was referring in this passage on 'Neo Pagans':
"There is a general and unmistakable tendency in neo-paganism to create a new, superstitious mysticism, based on the glorification of immanence, of Life and Nature, which is in the sharpest contrast to that Olympian and heroic ideal of the great Aryan cultures of pre-Christian antiquity. It would indicate much more a turning towards the materialistic, maternal, and telluric side, if it did not exhaust itself in foggy and dilettantish philosophizing. To give an example, we might ask what exactly is meant by this "Nature," on which these groups are so keen? It is little use to point out that it is certainly not the Nature that was experienced and recognized by ancient, traditional man, but a rational construct of the French Encyclopedist period. It was the Encyclopedists who, with definitely subversive and revolutionary motives, made up the myth of Nature as "good," wise, and wholesome, in opposition to the rottenness of every human "Culture." Thus we can see that the optimistic nature-myth of Rousseau and the Encyclopedists marches in the same ranks as "natural right," universalism, liberalism, humanitarianism, and the denial of any positive and structured form of sovereignty. Moreover, the myth in question has absolutely no basis in natural history. Every honest scientist knows that there is no room for "Nature" in the framework of his theories, which have as their object the determination of purely abstract equivalences and mathematical relationships. As far as biological research and genetics are concerned, we can already see the disequilibrium that would occur the moment one held certain laws to be final, when they only apply to a partial aspect of reality. What people call "Nature" today has nothing to do with what nature meant to the traditional, solar man, or to the knowledge of it that was accessible to such a man thanks to his Olympian and regal position. There is no sign of this whatever in the advocates of this new mysticism."

Evola's got many dissentors. There's a long list of accusations against him, "anti-liberal" being among them. Does he misunderstand the motivations of modern Pagans? At the very least, he does make sweeping generalizations. Alain de Benoist who is a very literate spokesman for Pagans certainly doesn't think Paganism is a lazy path, but rather encourages "everything that can allow a man to surpass himself." However, Evola's passage does highlight what the Setian author was speaking about. As best as I can understand Evola, he is speaking of a reaction to Christianity, and its concept of 'sin'. To him, such people are not on an initiatory path to better themselves, but to seek indulgence, 'eat, drink and be merry' sort of thing, riding on those currents of "semi-rational stimulus and response". 'Doing what comes naturally' comes to mind. But this is not the path of initiation. To evolve oneself into a more refined state of being takes effort. To succumb to 'nature', one goes the path of least resistence. The Setian opposition is to this 'path of least resistence'.

So therefore, it is not opposition to 'Nature'.

The following is from Wikipedia:
"Many scientists, who study nature in more specific and organized ways, also share the conviction that nature is beautiful; the French mathematician, Jules Henri Poincaré (1854-1912) said:

'The scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful. If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living. Of course I do not here speak of that beauty which strikes the senses, the beauty of qualities and of appearance; not that I undervalue such beauty, far from it, but it has nothing to do with science; I mean that profounder beauty which comes from the harmonious order of the parts and which a pure intelligence can grasp.[70]'" ^ (Poincaré, Jules Henri (1913). The foundations of science; Science and hypothesis, The value of science, Science and method. New York: The Science Press, pp. 366-7)

'Of which a pure intelligence can grasp', here he places this appreciation of nature into the realm of consciousness. It is with our consciousness that we know the beauty of nature. We return to our consciousness, our PSYCHE, and it is from this that all is known. Thus the roots of true 'nature' appreciation return to our consciousness. Psyche-worshipping is consciousness worshipping. Apart from a consciousness to give it meaning, 'nature' has no meaning. (The various critters in 'nature', to the extent of the consciousness they possess, do give it meaning. As I mentioned earlier, animals do have some of the 'Gift of Set', the gift of conscious awareness.)

I hope I've added some insight to this confusing question.