Its because they are all patsy's. The FBI find these people on psychotropic drugs who have a history of being crazy found on Facebook, twitter, etc which have CIA members in the company feeding them intel.
Then mysteriously the shooter has guns and ammo given to them by an undercover fbi agent or agents usually the real shooters. They tell them to go to a gun free zone and then FBI always kills them before they get interrogated. Remember vegas shooting. Alot of reports of gunfire from other directions.
Then immediately media swarms in to tell get rid of your guns. "Never get rid of your guns"
Solution: always carry even in gun free zone. If you are afraid of your kids getting shot at school you should homeschool.
You know you could do the same thing, you could even be the one to supply the drugs and get someone started.
That said I don't get why you are so quick to assume there's more too it than just someone wanting blood, it's naturally going to happen when you force different races to live around each other.