The kid was a big supporter of the 2nd Amendment. That doesn't sound like a Democrat to me. More info.
"Crooks tried out for the school’s rifle team but was turned away because he was a bad shooter, said Frederick Mach, a current captain of the team who was a few years behind Crooks at the school."
"Images of Crooks’ body reviewed by AP show he appears to have been wearing a T-shirt from Demolition Ranch,
a popular YouTube channel that regularly posts videos of its creator firing off handguns and assault rifles at targets that include human mannequins."
The 20-year-old nursing-home employee from suburban Pittsburgh who tried to assassinate former President Donald Trump was a registered Republican who packed explosives in the vehicle he drove to the campaign rally an hour from his home.
apnews.com