lex luthor's hatred of superman is entirely based in selfishness and ego. superman has what lex wants, no, deserves, and it makes him mad. he can't understand that superman is genuinely good, is helping people for the sake of it, because he can't do that. so superman must be up to something, and what better reason to make everyone love you than to take over the world?
in superman (1987) #2 lex investigates the connection between clark kent and superman, hires scientists to create a program to find it out, gathers evidence, and when he asks the machine, it tells him the truth. superman is clark kent. and yet, lex can not believe it. it's broken, it didn't work, because no being as powerful as superman would ever choose to act human. and he thinks this because he would, could never do so. although he casts superman as different, alien, other, he can not imagine a world in which superman isn't exactly like him, and doesn't want exactly what he wants. that's why he hates superman, because he can't fathom that not everyone is like him.