People kill strangers for one of two reasons, notoriety or for a cause. Notoriety is typically associated with a younger person while a cause is associated with an older individual (sometimes being married to a psychologist pays off). I expect we will find this individual (not a nut, perhaps a bit paranoid) will be much the same as the Arlington shooter who targeted Republicans or the guy who shot his neighbor because he is a Trump supporter. Basically the media is the underlying responsible party, as they are collectively making it OK to hate and harm those who believe in America, just as the CBS VP posted. We will not know specifics until his computers/papers, etc. are analyzed.