Society is very difficult to change, and activist groups aren't pushing in that direction as a whole (Autism Self Advocacy Network is far smaller than Autism Speaks.) Drugs are easy to make acceptable as long as the medical establishment is ok with it.
Hell, not that long ago lobotomies were accepted by the medical community. This is the problem with conditions that place a heavy burden on the parents, there is an incentive to act against the best interests of the children.
