Son Goku
Great Sage Equalling Heaven
To your 1st bullet point, Id argue that this point only applies to the robbers, home intruders, etc... that are committing criminal activities as a way to survive. Most of these school shooters weren’t criminals before the mass shooting. There's a possibility that these shooters would have never aquired these weapons if they had to commit a criminal act just to gain possession.
As far as the 3rd point, again how many of these mass shooters are using 3d printed guns, importing weapons, forging docs, etc...? At this point, they don't have to do any of these things and I'm not sure if there is enough evidence to suggest they would go through these lengths to carry out these acts.
He used the "committing crimes to feed my family" rhetoric.
Cool, you got it B.