You are apparently looking at this from the perspective of the victims only, but the burglars were also armed and shooting. They have been arrested for it: "... charges including first-degree burglary, conspiracy, shooting with intent to kill and possession of a firearm during the commission of a felony" [Oklahoma News 4, emphasis mine]

> good mass shootings in with other bad mass shootings

I'd certainly say that's better methodology than trying to define "good" and "bad" mass shootings and then only list the "bad" ones. (I don't quite see what's good about this shooting anyway, but I suppose you mean that the crime was stopped.)