One of the striking things about mass killings in the U.S. is how consistently we find that the killers were riddled with shame and sexual humiliation, which they inevitably blamed on women and girls. The answer to their feelings of inadequacy was to get their hands on a gun (or guns) and begin blowing people away.

What was unusual about Sodini was how explicit he was in his blog about his personal shame and his hatred of women. “Why do this?” he asked. “To young girls? Just read below.” In his gruesome, monthslong rant, he managed to say, among other things: “It seems many teenage girls have sex frequently. One 16 year old does it usually three times a day with her boyfriend. So, err, after a month of that, this little [expletive] has had more sex than ME in my LIFE, and I am 48. One more reason.”

I was reminded of the Virginia Tech gunman, Seung-Hui Cho, who killed 32 people in a rampage at the university in 2007. While Cho shot males as well as females, he was reported to have previously stalked female classmates and to have leaned under tables to take inappropriate photos of women. A former roommate said Cho once claimed to have seen “promiscuity” when he looked into the eyes of a woman on campus.

Soon after the Virginia Tech slayings, I interviewed Dr. James Gilligan, who spent many years studying violence as a prison psychiatrist in Massachusetts and as a professor at Harvard and N.Y.U. “What I’ve concluded from decades of working with murderers and rapists and every kind of violent criminal,” he said, “is that an underlying factor that is virtually always present to one degree or another is a feeling that one has to prove one’s manhood, and that the way to do that, to gain the respect that has been lost, is to commit a violent act.”

Life in the United States is mind-bogglingly violent. But we should take particular notice of the staggering amounts of violence brought down on the nation’s women and girls each and every day for no other reason than who they are. They are attacked because they are female.

A girl or woman somewhere in the U.S. is sexually assaulted every couple of minutes or so. The number of seriously battered wives and girlfriends is far beyond the ability of any agency to count.

There were so many sexual attacks against women in the armed forces that the Defense Department had to revise its entire approach to the problem.

We would become much more sane, much healthier, as a society if we could bring ourselves to acknowledge that misogyny is a serious and pervasive problem, and that the twisted way so many men feel about women, combined with the absurdly easy availability of guns, is a toxic mix of the most tragic proportions.