That's exactly the type of person that Steve is, though he isn't quite ready to just outright admit to it like that. He doesn't deny it either, though, so Mettaton can take that as his own kind of victory, if he wants.

When he explains that it had been one of the humans who was responsible, Steve's face falls and he looks down toward his shoes. It's not like he isn't aware of just how extreme some of the resistance members can get, and he isn't exactly innocent himself, but...

"I know it doesn't mean much coming from me, but I'm sorry that happened. You're trying to support us. Good deeds shouldn't be punished."

Too bad there isn't much Steve can do to fix it. He eyes the bandages on Mettaton's side with a frown, as if he could will the wound to get better. But no, he's no mutant.