Take for example, our resident autist 3B, who once saved a copy of some child porn that was being posted by Russian spammers. He took the picture and edited a black bar over the genitalia, and thought this would make it okay to re-post. In his mind, no visible genitalia means it is not porn, therefore it is not child porn, therefore nobody should consider it as such. He did this in attempts to start a discussion over why what appears to be a 10-12 year old child would have a piercing, and what bad parents they must have to allow it - completely disregarding the fact that the picture was still of a child prostitute somewhere in Russia.
The autistic person sees the world and other people as an incomprehensible mechanism, where right is what lets you do what you want, and wrong is that which doesn't. The only metric of morality is the autistic individual themself. This sort of literal sense of rules and social conventions, and the near-total disregard of other opinions, is what makes autistic people extremely dangerous. The less intelligent autist doesn't have the faculties to figure out how the rules work, so they just shut in and try to avoid upsetting anyone in fear of getting punished, while the high-functioning intelligent autist can observe and avoid committing social faux-pas, and can learn to be highly effective actors and pretenders - while still possessing the moral understanding of a two-year-old.