It may have been self defense in the moment, but he also went out there looking for trouble and found it.
He certainly wasn't expecting to have to shoot someone, but that's the case for most examples of self defense.
Inversely, someone shouldnt attack someone unless they accept the chance of death or harm.
A nice concession from you might be to admit that kids on your side maybe shouldn't attend protests with intention to do harm.
That's basically where right and left don't see eye to eye on this.
I dont think that is really the major party dividing line tho. I dont think most of the right thinks they went there with intention to harm, but to "defend".
I also think many people on the "left" take issue with someone putting themselved in a situation that could require lethal self defense, particularly over property.
With the exception of Luigi and I think that's more generational than left vs right.
I think if you reversed the roles, you would get much the same reaction.
Lets say you get some militia marching in the street, lighting cars on fire, vandalizing schools and businesses. Then one of the marchers chases down a counter protesters saying "im going to kill you", corners them, but gets blasted.
I think there would be a lot of rallying around the shooter if people wanted to try them for murder. People would say they were just taking out the trash and the deceased FAFO'ed.