I think they want to cure the people who suffer from their difference (autism, sexuality, you name it) because it seems easier than curing the society that make those people suffer in the first place. Easy as that.
"You're not feeling well because the kids bullied you after your monologue on the rise of syndicalism in Eighteenth-century English society? Here, take a pill" is definitely easier than teaching all those other kids and their parents (and possibly the teachers who didn't intervene) that they must treat everyone with respect, even if they don't understand them.
I can, to a certain extent, understand that some parents are devastated at the idea that their child is bound to suffer out there in the world. I doubt that when you're building dreams for what you hope your spawn will become and do, you hope that they will be humiliated, rejected, will have overall less prospects in terms of jobs, sensory issues, issues with food, etc. Everyone dreams of the perfect kid, I guess, and Aspies aren't seen as perfect (pff, little do they know how badass we are, surviving all that crap and then some).
But where I diverge is that just because it might be harder in society doesn't mean it has to be, doesn't mean it's not worth putting up a fight. If more people had the balls to do that, how much could be achieved? That's why I made the decision that I'm going to carry this Aspie flag high, even though I know it will come at a cost. I can, at my little level, be part of that "positive" representation (people have no clue how I struggle and usually think I have a good life. Gosh, I should have pursued acting, if only I wasn't so painfully incapable of loosening up). I'm not saying I'm going to become the poster child of Asperger's, or that people will idolize me like they idolize Beyoncé (still don't understand that), but if just one parent sees the things in common between me & their kid, and realize it's worth accepting them as is, or if one manager ever understands that hey, they can contribute to my company, I have to treat them well & maybe hire more, then I'll be happy.