@jeffcliff
> I agree that it's most likely a left leaning patriot
Why? Aside from the somewhat flippant counterargument I already offered, I'm not aware of any group on the US left calling for political violence. Unlike on the right where this is par for the course these days among Team Orange Felon.
Secondly, even if a leftist shooter was conceivable, they wouldn't have chosen a political rally. Plenty of other places where there wasn't a risk of bystanders being hit.