It's this:

Once again, the only true gun control in America is when the shooter finally puts one of his guns to his own head and blows his own brains out.

But what does Elliot Rodger, the alleged UCSB shooter, have in common with Adam Lanza (the Sandy Hook killer)? Not just color of skin, which is not that important. What is deeper and more troubling is the combination of their ages (between 20 to 24) and sex (male). Look at the numbers (a PDF) in the Census Bureau's statistics for "Murder Victims—Circumstances and Weapons Used or Cause of Death: 2000 to 2009." Men in this age range are more in danger, and as a logical consequence are more dangerous than men in all other age groups. (The statistics concerns victims, yes, but male victims tend to be like their killers in sex and age.) Indeed, it is not irrational to propose that guns be banned for males of all races until the age of 25—a more effective ban would be until 29.

The picture is clear. Men are really bad news in the first half of their 20s. The fact that the age area of male danger is consistent in all races, means that the culture/gene relationship is exceptionally volatile (there is no such thing as just genes; there is always genes and the natural/cultural environment). Also, the number of female victims between 20 and 24 is pronounced; but my guess is that this is a consequence of these kinds of women tending to associate more with, and therefore being exposed longer to, the males in the dangerous age group—an age group that's armed by the NRA.