it's not merely a question of "you fucking take care of them, then". it's the severely autistic people themselves that have to live through a condition of being unable to speak, or having to wear diapers into adulthood, or being stuck in perpetual pain. there's no way to attach dignity or meaning to this, and if your god insists on it then your god is a piece of shit that should be tied to a cross and set on fire and burned until it dies.
if we can eliminate that suffering before it starts, we should do that.