That was an response to the previous poster's incorrect observation about hearing "nothing in the way of mass murders on airplanes."

It appears that you incorrectly interpreted it as a complete list, as you concluded that only two incidents have occurred. http://listverse.com/2014/03/26/10-people-who-committed-murd... gives other examples of people who have committed mass murder on an airplane, including http://en.wikipedia.org/wiki/Continental_Airlines_Flight_11 (as a consequence of a suicide-by-bomb insurance fraud).

Also, the context was "mass murders on airplanes." Mass murder means typically 4 or more deaths. I have found many murders which took place at churches in the US [1] and ending up with one or two death. However, I haven't haven't found much in the way of mass murders of the sort that is supposed to be identified by security theater measures.

[1] If we go outside of the US then there are certainly metal detectors at some synagogues, bomb detectors at Mecca’s Holy Mosque, etc.

Over the decades of following online discussions, I'm growing ever more irritated at pedantic declarations of wrongness by countering reasonable generalizations with obscure/rare exceptions. Yes, out of the total vast number of commercial "airbus" flights ever, a minuscule number have suffered such incidents; likewise, a tiny number of holy sites are secured due to extreme attraction of violent nutjobs; taken in context both in absolute percentage of instances and in this being a casual discussion involving short comments of understandably less than peer-reviewed encyclopedic thoroughness, we don't have to spend time arguing minute absolutes.