Probably the whole thing with being intoxicated and writing stuff about conspiracy theories and the Illuminati made him look mentally unstable and possibly dangerous. It's usually the delusional people that actually make attempts on famous people and occasionally succeed.
I can't remember the details, but I think a guy in my husband's tiny Kansas hometown was shooting his mouth off in a local bar years ago about killing the president and ended up getting a visit from the Secret Service. He must have ticked somebody off enough to report it, but they take virtually every threat made against the president seriously from what I've heard.
No sense of humor, those guys.