I do not believe a majority of psychology professionals actually want to reduce mass shootings. I believe that they slowly engineered it so folks who'd be in a minimum security prison end up so economically precarious the world becomes an open air prison unless you're lucky enough to literally have some contacts in civil society.
(But that only helps for a test case, not your normal everyday... people being rude to you from the day you were born for things you didn't choose.)
I'm grateful for the many, many folks who've gotten kinder since Columbine, but a small but vocal minority of teachers and others with authority over children continue to, on ocassion, abuse their access in ways that induce mass shootings.
It is not acceptable to kill people, but someone who instigates that behavior should not be treated nicely let alone given cushy stable employment from which to lobby for more ways to terrorize their victims.