Then I take it back, the news media are fucking terrible at disambiguating any of this. I see these articles 'Hollywood Director confirms son was shooter. Father blames NRA...blah blah' they really need to learn how to write.
If the NRA had any sense, they would come out strong against crazy people and for more tracking of therapy. You wouldn't catch everyone, but I guarantee if this dude's psychologist was made aware of the PUBLICLY posted videos (no confidentiality issues) and police asked him if he was well enough to own a firearm, he would have said 'hell no'.
Still, with the rampant misconduct of police officers dealing with otherwise law-abiding citizens, I find it hard to believe the dude posts threats online and they can't do anything about it.