If all of the mass school shootings which have taken place in the last decade and a half had occurred in majority minority, typologically urban, population dense, impoverished communities there is no doubt in my mind that the scrutiny of those events would include a critique of each and every one of the aforementioned characteristics.
From the Marysville, WA Wikipedia page:
Since, in each and every case, the opposite is true, each and every one goes unmentioned.