[Wanderer99]

I grant you that they were all insane, and on brain medication -- but it is also interesting that these gunners came from ostensibly gun-hating Democrat families.

Not all gun-hating but definitely amoral/atheist and socially liberal.

[El Cid]

Not all gun-hating but definitely amoral/atheist and socially liberal.

You are correct. Also, I remembered later that I had forgotten the Korean-American kid that ran amuck at Virginia Tech. It turns out he came from a strong Christian family, but alas, Satan used his mental illness to drive him to evil - and to fit your definition of one who is an amoral/atheist (and likely socially liberal).
Per wikipedia:
he "railed against his parents' strong Christian faith." According to one report, Cho Seung-Hui had left a note in his dormitory which contains a rant referencing Christianity and denigrating "rich kids." He stated that "Thanks to you I died like Jesus Christ, to inspire generations of the weak and defenseless people."