Because they hate the idea that genetics defines them in any way at all.

Genetics is for "animals". Humans are magical beings made out of fairy farts, and the idea of humans being limited by nature offends them.

Note how they defy that genetics defines sex ... they use the word "gender" instead, and think that wearing dresses and cutting off their dick somehow makes a man a woman.

Mental retardation? Oh, well, that's all the "poisons", it can never be my shitty genetics that caused my kid's mental deficiencies ....

Humans hate thinking they're a part of nature until it comes time to justify killing other species.

They also seem to think that "eugemics" means "killing" .. and what the fuck is wrong with sterilizing some sexually aggressive retard with no impulse control? Or aggressive retards in general?

I once met this ... couple .. that were passed off as a "married" couple, because they openly talked about ... stuff .... until someone slipped that their parents were "rich jews" who abandoned them for being retarded ... the look on his face when I said "both pairs of parents?" told me they were what I suspected, fraternal twins .... imagine the monster they might have spawned in they hadn't been fixed back before they banned mandatory sterilization of these .. humans (they're not people. If a sign language using chimp can't be a person, then neither can a goddamned abomination.)