Autism is comprised of a number of symptoms that go together to make a whole. Henceforth, there are still people who believe it isn’t real, but simply an unnecessary name for a conglomerate of behaviours.
I think the argument is that if you put an Autistic person in a room by himself, then what Autistic behaviour exists? Sure, they may line things up, or spin, or flap, but we only find this behaviour odd because it’s against mainstream social consensus. As for problems with social interaction and communication problems, what problems exist when there is no one to communicate or socialise with?
In short, Autism is real – but often (I say often – sometimes there are co-morbid sensory and other problems that are debilitating in and of themselves. Here, I’m talking about Autism on its own,) exists as a disorder because other people have made it real. It exists in the differences in behaviour than those stipulated by a general consensus of social normality. It only exists because those with Autism break the rules, and bring about change from the norm, which is not just a shame, but is also, when you think about it, beautifully ironic.