100%, this is my take.
The guy was a registered Republican with very little social media presence. According to classmates he was bullied relentlessly throughout high school, and then got into firearms and other weaponry online as he continued to self-isolate.
I do think he was attempting get Trump though, for whatever reason. Fame, notoriety, some belief that was festering that he didn't articulate. Perhaps it was to strike back at the type of people who had mistreated him in that small town for so long. No manifestos or screed found yet, and I doubt they will be found.
But all in all, it's essentially just another mass shooting in America, one that happened to be in a more publicized setting, thus meaning has been placed upon his actions which might not have truly been there.