There is a connection between the two boys that has led them to a place where this seems to be acceptable behavior. It's something they share but is also fairly unique since most families aren't producing multiple potential or actual school shooters.
I am interested to see what underlying causes are identified, if any.
It's almost always bullying or abuse at home, but no one ever admits it. These people were mentally and/or physically tortured by other people. They want revenge or to inflict a fate worse than they were given. But we keep acting like bullying still isn't an issue and that these people were just messed up naturally.
My bet is on dysfunctional family - maybe child sa, maybe mental illness or other trauma/combination of traumas. Our society is unstable (Ie: pandemic) and they feel out of control, maybe abandoned, and this is the only way they feel powerful.
Because its one if the few places you can be nearly 100% certain no one will fire back. Shoot up a restaurant, mall, church, park, etc you will receive return fire from lawful carriers almost immediatly, especially in Texas.
She did it knowing that her family would be lambasted by the public as well. Maybe dont try to shame them or group them together--she did the right thing. The next mom might not if everyone dogpiles onto this one.