The guy was clearly mentally ill if you'd read this Washington Post article:
https://www.washingtonpost.com/local/public-safety/law-enforcement-officials-identify-shooter-at-congressional-ballgame-as-illinois-man/2017/06/14/ba6439f4-510f-11e7-91eb-9611861a988f_story.html

I hate how the media is using this to take sides of one political party versus another but at the end of the day, sure this guy was progressive, but he does have a history of violence and abuse and strange behavior (shooting guns at nothing in the wilderness).

Anyone using this for any political agenda is just as sick as this guy was.