I agree with you that it's more nuanced than the binary thinking often advocated. But I also think that "evil" exists in the world: ISIS is evil, the Nazis where evil, serial killers are evil, and so on. I think the question of "do they think they are doing good or bad" is an interesting question as well.

There's also, like you say, people who do things we perceive as "bad", but it often comes down to misunderstandings of motives, imbalances of power and so on. If somebody steals bread to eat, it's not a good thing, but I can't condemn the act either. As somebody who likes to think they're a force for good, I should probably see what I can do to improve their situation so they don't have to steal in the future.