Singal and the jury have it right.

The moment he fired his rifle, he was not legally guilty of murder because he shot in self-defense.

The moment he decided to go into a town hoisting an automatic rifle, let alone into a town where rioting as breaking out at night, he was morally guilty of needlessly and dangerously provoking others.

He was mentally and biological a juvenile. His actions should be judged through that lens. Also, in the coming weeks and months, the amount of credence given to his opinions about politics, gun rights, etc., should be in alignment with his mental and biological age. The adults in KR's life should encourage him to keep his head down, fade out of the public eye, and move forward in his life, but I doubt the media will allow it.