It seems that Rosenbaum was the one who started things, had no interest in the rights of black people or anyone else, and was just using the riots as an excuse to act badly. Perhaps I am wrong, but that's what the available facts point to - including the history of the crimes he was convicted for.

As such I don't consider him a "child lover" in any significant sense, and of course regardless of his past, attacking someone for trying to put out a fire that was threatening the public, and threatening their life in doing so, is the sort of thing that is likely to yield a like response. Rittenhouse may or may not be a decent guy, but he wasn't threatening anyone or committing any crimes when he was attacked and his life was threatened.