Even if it's zero, he could still be a shitty person who shouldn't have access to that button. If anyone should have such access at all, of course.

Is that the du jour unit of measurement for morality now?

I suppose as an American taxpayer and American voter, he is responsible for as many ethnic cleansings as anyone else. Supposedly, Armenians leaving Nagorno-Karabakh is ethnic cleansing, and the US did give aid to Azerbaijian so that makes Americans facilitators of ethnic cleansing, though admittedly so are the Canadians.