The thing about gun nuts is that every single one I've known had a vigilante fantasy. Basically they all wanted the "opportunity" to kill a black person.
I don't mean all people who own guns. I mean gun nuts. The type who obsess about them, and are always packing.
It doesn't sound like this murderer was a gun nut (though we really don't know at this point), but all the people who think the solution is to arm every toddler are.