Well to be fair, I wouldnt put a gang related shooting at a school in the same category as a 'classic' school shooting. Not that they are any less dangerous though.
I'm gonna kind of go in the other direction.
I don't think we should discount a shooting just because it is gang related. Gun violence is gun violence, and what the "gun nuts" are trying to do is pare down the definition to the point where it doesn't even exist anymore.
Kid shoots another kid? Sorry, doesn't count if it is "gang related." Kid gets shot in an accidental discharge of a firearm? Sorry, that's a "safety issue." Bunch of kids get shot by a crazed gunman? "Hey, did we mention we support mental health screenings?" Whenever anyone tries to talk about possible solutions to gun violence, the gun lobby whittles away at the definition so that only shootings by lawful gun owners are on the table, which can then be easily dismissed as mental health problems or "that person wasn't a real responsible law-abiding gun owner after all."