In regards to the existence of self-propagating memetic compression-waves of information, energy and their associated semantic matrices passing through cultures and individuals; it is far more likely that mass shootings recursively generate behaviours such as mass shootings. We are witnessing serially deceptive (or inept) attempts to do and blame everything except the prime movers of these trends which, in essence, can perhaps only ever be the ready availability of the weapons with which these crimes are committed.
The conditions which exist within a culture which might allow, indicate or in some sense cultivate the psychological and behavioural possibility of and preponderance to mass shootings is complex and not attributable to any single cause. There do however remain organisational and material facilitators. The sociological, psychological and economic conditions which lead to the high availability of the tools used in these events can not in any sane or sincere analysis be excluded from implication.