I think its more likely this was a some mentally unstable person (white, middle aged, male), more than likely living a life controlled by medication, but went off his meds, started to hear voices in his head telling him to below up the more vocal adversaries of Trump and acted on it. Once found, he will either get the treatment that he needs, or he will kill himself or be killed by law enforcement, as he probably believes he's a martyr to the cause..
Or, Elvis told him to do it.