Excellent piece. I will be linking to this piece to counter guns for everyone rhetoric, which, unfortunately, seems futile as it is resistant to logic.
One thing to add to the mental illness portion:
So, basically, whatever is going on with masculinity in America seems to make some men raging shooters.
And to the MRA who believe men are suffering under the oppression of women: yeah, right. And to the MRA who believe masculinity is harmed because of feminism leading to men performing shootings, uh, right: any kind of masculinity which reacts in such a fragile manner to cultural changes that they go and shoot innocent people is not masculinity [or humanity] in my book.
Just getting ahead of the MRA, MRA sympathizers, and red pill people out there.