PETA's overtly confrontational approach was likely driven by empathetic people struggling to just live their lives knowing humans are 'passively' responsible for incomprehensible suffering around the world. In this scenario, how could you not feel compelled to wake people up? Unfortunately, as sure as we struggle to transcend our primitive tribal instincts, even the most altruistically motivated groups develop their own identities that need to be fed.
Despite this, and as someone who is on the spectrum, I struggle to relate to the idea of being offended by any of this. Perhaps I am in a weird bubble, but I also find it very difficult to imagine any of the autistic people I know being offended - whether it's real or not. In my experience, autistic people tend to be able to be a bit more detached and able to hold opposing views in simultaneity. Obviously I could be wrong, but to me this supposed anger seems more like defensive NT virtue signalling: PETA makes me so fuckinmad because I am unwilling to work on understanding my actual emotions -> omg PETA is attacking the autists I normally make fun of?-> not on my watch!
It is interesting to me that people can take such a hard-line stance against an organization like PETA, while having unlimited mental gymnastics for countless other organizations - including those with no hint of morally redeeming character - just because they personally find them convenient and/or enjoyable.
Your ideas about euthanasia are dumb.