They wanna go out with a bang
Why not just kill yourself though. That gets just as much attention from family, friends, classmates, family friends, teachers, hell anyone that was involved with you in any way tbh.
If you really have to be an attention seeking prick, just kill yourself. At least people will want to remember the good shit.
Shoot up a school and you're a piece of shit no matter how fucked your head is.
But any clout is clout these days, look at Ted Bundy and Jeffery Dahmer ffs