Some puzzling oddities to this. The man who was shot had a swastika tattoo on his arm, but covered with a red circle and diagonal line. But this was why it was initially thought that he was a neo-Nazi. In fact he is a leftist opposed to the speech.
The 50 year old Asian man who shot him was in line to attend the speech, when this individual allegedly assaulted him, and he responded by shooting him, and is claiming self defense.
The above thread has more here, videos, links, etc. The guy shot is a professional protester - supported Bernie Sanders. The shooter looks like he was trying to help another guy that had his red hat (MAGA?) taken, and then he was attacked as well.
A twitter said one of the protesters had brass knuckles and was beating a guy - but who knows. If so though, reminds me of that movie line by Sean Connery “Well, ain't that just like a Liberal - brings brass knuckles to a gun fight.” (Or something like that!)