They truly don't. That's just part of the alienation.
When the opposition is called evil it's not because logic dictates it must be evil, it's called evil for the same reason it's called ugly, unintelligent, weak, cowardly and every other sort of derogatory adjective under the sun.
These accusations have little to do with how often people consider others things such as "ugly" or "weak", it's just signaling.
I disagree. There's an awful lot of "my position is obviously based on the data, so if you disagree it must be because you want to be evil". (In my opinion, the left does this more than the right, for whatever that's worth.)