If he was radicalized then jihadist makes the most sense. If he was Antifa or Neo-Nazi he would choosing his victims from the groups he hates. This guy seems to have scoped out several events some of which would have had a leftist audience and the Vegas event which would have had a mostly white conservative audience. The politics of his victims didn’t seem to matter. That leaves jihadist.
What this really means is they do know and it is political kryptonite for the democrat party.