[tzs]

What does that have to do with US domestic terrorists, which is what the study concerned?

Trump is the only one on your list where it was a US domestic terrorist.

The shooter in that case seems to have been more right-aligned than left-aligned but there is nothing definitive. He donated $15 to Democrats when he was 17, but a few months later when he was 18 and registered to vote he registered as a Republican. A social media account that is thought to be associated with him had a lot of anti-immigration and antisemitic content.