If you refer to statistics, and there is official international statistics on that matter, please provide reference. So far I never see any evidence for your point of view. You refer to it like commonly "known" fact, but it is not.
It should also be noted that the data set they used only include mass killing with guns, and not mass stabbings. Those also happens, including here in Sweden a year ago at a school. But if you don't like that data then bring more and we can discuss.
Two things pops out. First that the variance is massive within the united states. The second part is that 63 percent were suicides. It is very doubtful that a single correlating factor accounts for the variance.
