The thing about Autism Speaks is that they chose a bad name. Their name should have been “People who have met people with really bad autism speak.” It’s pretty clear that they’re looking to “cure” autism, when the fact is that a lot of autistic people(not all, but a lot) are perfectly happy just how they are. As an autistic person myself, I don’t want to be “cured,” I just want a little compassion when I am in a situation that’s the result of my own misunderstanding.

tldr: They think it’s a disease because they’ve clearly never bothered to ask autistic people what they think. They’ve only asked those who are annoyed with autistic people what they think.