I’d say subculture is fine. A subculture doesn’t have to be bad or annoying. Identifying with autism is also totally fine. Recognizing kinship isn’t bad.

Where it goes wrong is using it as an identity outright. “Sorry, I’m autistic” is just fucking more annoying after someone does something annoyingly autistic. Being autistic doesn’t mean you literally cannot learn good social behavior. By the time that is true, there is definitely something more serious than autism involved.