From Slate:

It’s always been complicated. Who’s the good guy with the gun? Was Rittenhouse a bad guy who became a good guy? Was he always a bad guy? Were there bad guys and good guys in the crowd who were armed? I think the answer is always complicated. But I think it’s different than a mass shooting. It’s different than somebody who goes to the crowd with the idea that I’m going to kill people. And I think that’s really important to keep in mind, especially for people on the left, that he didn’t go there to kill people, even though him being there was just the worst judgment in the world and stupid and he never should have been allowed to be there. And it’s a true failure of our society that no one said to a 17-year-old kid, “You don’t go do this because you might shoot somebody. Even if you don’t want to. You don’t go do this.”