Or that the spectrum is more like a wheel than a linear measurement. DC is articulate, smiles, hugs, chats about interests, and so on, looks like your typical teen. Except DC hasn't got the cognitive skills to match that chatty, social exterior. No stranger awareness, no sense of personal safety, no self-control, poor working memory, poor fluid reasoning, cannot adapt 'in the moment', doesn't cope with change, doesn't understand boundaries or social expectations, and so on. Pick your subject and he can tell you all about it, ask him to go to the shop and buy you a loaf of bread and he's going to massively struggle. Ask him where his shoes are. Go even more simple, ask him to tie his shoes. He can explain to you all of the steps needed to tie shoes, might even give you a little history lesson about shoes through the ages, but ask him to execute tying those shoes himself and he can't as his brain can't translate that knowledge into the right hand movements carried out in the right order.
But people see him chatting and smiling and think well he's not really autistic is he, just just a touch of autism not full blown autism.