Isn't good and evil ever present universal concepts? Without one we couldn't have the other, so couldn't we say thay evil is created by good and vise versa?
And no, it's not based on subjective criteria - it's based on a universal (well, Earth-i-versal) objectiveness.
Humans consistently do things that they believe are wrong. Does it matter if the things are wrong? No... it matters that the humans BELIEVE the things are wrong.
What is evil? Knowingly doing things that are wrong.
It takes a lot to find someone who doesn't violate his own principles on a consistent basis. I know a few people like that, and I'd never insult them by calling them humans.