Wait, wouldn't it make more sense to believe that the reason most mass muderers are on SSRIs is because they are mentally unstable individuals with troubled pasts that probably needed attention, whether it was negative or positive? Blaming SSRIs specifically when so many people are on them as the culprit or a major influence on their decision to go commit murder seems a bit... premature. There would need to be a lot larger group of studies done. It is true that too much can lead to suicidal ideation and worsening of depressive symptoms, but if a doctor is doing his or her job, then this issue should be rather moot. If anything then, blame the doctors prescribing it rather than the drugs. So many factors go into committing a crime though that I feel it would always make more sense to blame environmental factors, mental illness, predisposition to violence, anger management issues, the community, previous behavioral issues, and personal history.

Don't get me wrong, I think SSRIs are terrible drugs without much evidence supporting the wanton prescribing of them to patients that could receive better and more effective help without being subjected to withdrawal symptoms upon finding out the drug is useless, but blaming them for mass shootings is over-the-top at best. Pointing out the correlation is fine, but using it in the context that you are is implying blame.