So it turns out Hale did not do this on the spur of the moment but had planned things out in detail. Hale surveiled several targets choosing the school because of it's lack of security. So it may have nothing to do with it being a religious school. I haven't seen verification he was a student there* and if so it was in the distant past. Hale also had lots of ammo and left a manifesto. So whatever was eating at his soul has to be pretty bad for him to kill 9 y/o kids and staff when he apparently did not know any of them personally. Cops did good to stop him fairly quickly.
He had no criminal record. Hard to see what could have prevented this given Tenn. existing liberal gun laws. And it's not like someone else bought him guns or he bought them illegally.. Perhaps the manifesto will shed some light.
*ETOA: CNN reports police confirm he had been a student at the school.
https://www.cnn.com/us/live-news/nashville-shooting-covenant-school-03-27-23/index.html