1. His long planned and carefully executed purchase of a virtual armoury of unprecedented scope and scale guaranteed that very armoury would inevitably become the central focus of the media.
2. His assiduous removal of evidence of any tangible motive also removed the possibility that the news cycle might move on from guns - simply the means of the killing - to considering the more interesting issues of motive and message - be it political or economic or environmental or anything else.
3. This man was a highly methodical and systematic thinker. Nothing in the scenario that unfolded was left to chance - even down to positioning cameras to surveil the corridor. It is therefore inconceivable that this was all done in this precise manner for no reason. That there is no message.
But of course there is indeed a message. It only happens to be implicit instead of explicit. That message is 'guns'. And that message is being trawled over every minute of every day on every network in America. Given the nature of the man and the facts this is not a chance outcome. On the contrary given the known facts it is indeed the only possible outcome. An outcome so obvious that anyone given the full story beforehand would have predicted as inevitable.It makes as much sense as anything else I've read on the topic, though there is no hard evidence for it so far.
4. The people he chose to kill supports the hypothesis on 'guns'. Country and Western fans are virtually guaranteed to own or at least to defend the ownership of guns. By a certain logic this provides the gunman with two sound moral positions (because it is not beyond possibility he has a conscience):
First - While killing a very large number of innocent people is an horrendous crime it is nonetheless entirely justifiable - in moral terms - if it causes a restriction on guns. Because such a restriction would - it is widely held - save innumerable lives in the long run. There is no evidence for this but it is still a widely and passionately held belief.
Second - Since the people he is shooting are actively or passively defenders of guns and an obstacle to gun control they are by definition responsible in part for all the people who have been and continue to be killed by guns.