I don't agree with it, and I don't know why people would wish to worship evil, and I think that my being friends with a satanist would be difficult, but thats because I'm a Christian so we'd be friends with completely opposite views. I'd also feel I was being unfaithful to my God. I don't hate satanists, I just don't understand them at all. I try not to hate anybody though.
Satanists don't worship evil. In fact, there is alot in it that I agree with.
This is a pretty good source of information.