I think you have to include power in this answer as well, an instinctive drive for domination.

At the same time, I think looking at it as a problem of feeling morally threatened fits in as well, but related.

From my point of view there are two basic moral regimes (from nature): Competition and Cooperation.

Human society and civilization has always been about cooperation. It's why we evolved big brains. Nature is usually about blind competition, so we have that instinctive strategy too. To those that follow either moral strategy, the other strategy looks immoral. While part of a cooperative strategy is to tolerate differences, to a dominance strategy, different values must be ...annihilated. (By the way, that is how nature, red of tooth and claw, does it. Humans shouldn't though.)

Superhuman will not come from nature's path. That will only lead to being animals. That is not rhetoric. My work shows that because that strategy makes certain developments impossible that humans need to achieve their aspirations. Humanity only has a furture as more than animals if we use strategies we create that nature cannot.

Fascism is not a fantasy. It is a viable strategy. The problem is it will put a wall in front of human development and humans will lose thir future potential. We will never have the destiny that humanity has worked for since before the Ancient Greeks could look out their city gates to see "man in nature", a harsh brutish sight that they wanted to rise above.

Cooperative humanity of society and civilization are the descendants of fascist ideology. Their strategy has no future, but cooperation does and it offers a future for humanity where we can achieve ancient aspirations to be more than animals and in that sense, far superior morally.