Should depend on the law and the evidence. The reason Kyle was down there does not legally matter. As soon as Rosenbaum threatened him and gave chase he had a legal right to self defense.

I personally think he's a moron who put himself in a bad situation. But so did the men he shot, especially Rosenbaum who wasn't even there for political/social reasons and was simply a violent criminal who stumbled upon a chance to get violent. The entire night was a series of bad choices by all involved. But at the end of the day, the only thing that matters is what the law on the books in the state of Wisconsin says.