That's the idea. Evil is apathy. Peter Singer is willing to make personal sacrifices to help others, and tries to figure out how to help people as much as possible with limited resources. There's no Evil Peter Singer that makes personal sacrifices to hurt others and tries to figure out how to hurt them as much as possible with limited resources. Evil people are people who just don't care, and harm others whenever it benefits them.

But maybe in something like D&D where there's demons, they actually care about causing suffering and the people we think of as evil are merely neutral.