Gates is probably the least evil person I can think of. The truly decrepit evil lies in the halls of our government now.
Read through the antitrust stuff that happened in the 90's. He's not a good guy. I know he puts on this persona of "geeky nice guy", and I'll admit that I fell for it too long, but he's a multi billionaire, and like other multi billionaires he is not a good person.
If he is the "least evil person you can think of", then you're not thinking very hard.
You could probably amend this to "billionaires", instead of the qualifying "multi billionaires".
ETA: You know, I was thinking, just because I qualified it with "multi" in front doesn't really imply that single-billionaires aren't evil. I didn't specify that serial killers are evil either, but I don't think me not specifying that implies that I think they're fine.