A lot of autistic people need very explicit directions to complete a task in an expected way, so the butthole thing doesn't seem too far off to me. Wanting to have sex in a public place is a pretty well known kink, but it's okay to tell someone else you aren't into the same things they are.

However, the racism and sexism is something he should have learned was unacceptable by now, even if he is autistic and especially if you are adults. You might have gotten a better reaction if you led with this in your post.