Diversity in ant behavior directly benefits their "front line". More scouts/backup depending on how timid or aggressive they are.

diversity in cowmilk output (lol) in cows for a farmer isnt something desirable, atleast one area i know something about.

Surely you've noticed that this only applies to a population that is being exploited as a resource and prioritizes a specific trait or traits that are desirable to the exploiter rather than traits that contribute to the organism's well-being. That's what eugenics is, and what you are advocating for. It is not better for humanity or even for the individual to eradicate autism, it is better for our exploiters.