Often you step into the mental landscape of a mass murderer and find nothing but paranoia, nightmare logic, snakes eating their own tails. But compared with the mysteries of Tucson, Newtown and Aurora, this case has an internal psychodrama that is much more recognizable, a murderous logic that’s a little more familiar. The Santa Barbara killer’s pulsing antipathy toward women, his shame and fury over sexual inexperience — these were amplified horribly by mental illness, yes, but visit the angrier corners of the Internet, wander in comment threads and chat rooms, and you’ll recognize them as extreme versions of an all-too-commonplace misogyny.

I’ve written before, in the context of the abuse that female writers take online, about this poisoned stream’s potential origins. The Santa Barbara case hints at one such source — the tension between our culture’s official attitude toward sex on the one hand and our actual patterns of sexual and romantic life on the other.

The culture’s attitude is Hefnerism, basically, if less baldly chauvinistic than the original Playboy philosophy. Sexual fulfillment is treated as the source and summit of a life well lived, the thing without which nobody (from a carefree college student to a Cialis-taking senior) can be truly happy, enviable or free.

Meanwhile, social alternatives to sexual partnerships are disfavored or in decline: Virginity is for weirdos and losers, celibate life is either a form of unhealthy repression or a smoke screen for deviancy, the kind of intense friendships celebrated by past civilizations are associated with closeted homosexuality, and the steady shrinking of extended families has reduced many people’s access to the familial forms of platonic intimacy.

Yet as sex looms ever larger as an aspirational good, we also live in a society where more people are single and likely to remain so than in any previous era. And since single people have, on average, a lot less sex than the partnered and wedded, a growing number of Americans are statistically guaranteed to feel that they’re not living up to the culture’s standard of fulfillment, happiness and worth.