> Your explanation is missing the anger factor. <
You make a good point. But there has to be more to it than just that. Back when I was a youngster (1960s), some kids were bullied. Some kids couldnt get dates. Some kids were perpetually marginalized.
But nobody shot up any school or any mall.
Guns were also readily much more available HOWEVER kids were not put on psychiatric pharmaceuticals at the drop of a hat AND we did not have VERY VIOLENT video games that we sat in front of for hours on end to desensitize us to such things as mass murder and just killing in general!!!
There was no internet then. Fast forward to 2019 and one of the few things we already know is this killer said he spent at least 8 hours a day online.