FireTbh having an opinion about someone based on what you read about him is pretty common, you cant tell me that you have no opinion about Hitler, or members of the IS for example. You dont need to meet someone in person to get an opinion about him, imo public behaviour reflects a personality more accurate than personal meeting, because people tend to be nicer in general when you have a private talk.
you do actually need to know how he is irl to judge him.
people judge hitler because of the actions he did against other people.
people judge sheepy because of what he writes on the forums.
I fail to see how you even compare between the two.
afaik he does have some sort of autism, it doesn't mean people won't hate him because of what he writes, but I feel that people just care too much.
just ignore him if you think he is writing stupid shit, getting into an argument with him doesn't seem to help.