Personally, I don't think any kind of gatekeeping of the Autism label is going to prevent people from being arrogant, ignorant, and self-involved... it reminds me a bit of the discussions in the queer community of how we can keep out assimilationists and "straight" interlopers who are just pretending to be gay, or are not gay enough. I don't think the solution is invalidating anyone's identity or restricting based on identity. I think the solution is forming communities that have a true political education and understanding of the core values that are essential to Autistic liberation (or to queer liberation, as the case may be). It seems to me the fundamental issues are often questions of values differences, or of people's education on the subject at hand being quite lacking, rather than them not truly being who or what they say they are. That's my take on it. We will always have to stay vigilant and have these hard conversations and root out nonsense.