Hours before Alek Minassian drove a rented van onto a crowd in Toronto and killed 10 people, police say, a Facebook account linked to him announced, “The Incel Rebellion has already begun!” It praised “Supreme Gentleman Elliot Rodger,” a 22-year-old who killed six people in a stabbing-and-shooting spree in 2014.

“Incel,” or “involuntarily celibate,” isn’t so much a movement as a label used by a group of people drawn together by the same frustration — the inability to attract sexual partners — who blame their lack of conquests on the women who deny them sex and the men supposedly cornering the market.

Most people never heard the term before the Toronto attack, but it has been used for years in online forums. And it flags a culture we should take very seriously because of its potential for violence. That stewing resentment, after all, may not only be behind Minassian’s actions: He certainly wouldn’t be the first man to blame a murderous rampage on sexual failure.

The incel world deifies Rodger, a self-proclaimed “kissless virgin,” who left behind a manifesto. He blamed his killings on women he felt had unfairly rejected him in favor of less worthy men.

And he’s now held in high regard in the dark corners of incel forums, where men describe the violent rage they would unleash on a society that has supposedly made sex too difficult to attain.

Toronto Sexuality Centre Director James Cantor says incel is not “some organization that is joined by some common principles” but rather “a group of people who usually lack sufficient social skills and they usually find themselves very frustrated.” This frustration is voiced on online forums, such as 4Chan and Incels.me, where angry men convince other angry men that their collective inability to land dates is a vast, unjust conspiracy.

“And when they’re surrounded by other people with similar frustrations, they kind of lose track of what typical discourse is, and they drive themselves into more and more extreme beliefs,” says Cantor.

Those beliefs include encouraging acid attacks, rape and murder in retribution for society’s failure to make sex easy for them. In 2017, Reddit banned a subgroup called “r/Incels,” which had garnered about 40,000 members, after the site updated its policy to prohibit content that “encourages, glorifies, incites or calls for violence or physical harm against an individual or group of people.”

A look at Incels.me, where many Reddit users fled to continue wallowing in their misery, gives you a glimpse into their hatred: Posts declare that gamer girls (women who like video games) deserve to be sexually assaulted, call women selfish for “exclusively sleeping with the top % of male[s]” and claim “the blood of victims of terror attacks is on the hands of females.” Comments not only agree with the original poster, but often try to one-up the violent rhetoric.

To be sure, not all self-described “incels” condone violence. And, as Cantor points out, some of the more fevered-up ones can be helped with counseling.

Yet it’s easy to see how their mutually reinforced anger could lead some to lash out. If Minassian’s post represented his beliefs, the online groups that fed his hatred — and any violence he committed — are partly culpable.

Incels’ inability to connect with others may stem from a lack of social skills. But when they abandon the pursuit of relationships in favor of long-winded posts about their anger toward “femoids,” one’s sympathy wanes.

These men imagine themselves victims because they weren’t blessed with good looks, money or charm — attributes they claim women prefer over, say, a good personality (which I’m sure they could offer if only they could stop calling women selfish whores on all-male forums).

The rhetoric on incel forums is dangerous, not only because it ­fuels hate and self-pity, but because it often romanticizes and justifies violence and bolsters the belief that life without sex is meaningless. That led to Rodger being treated as a martyr, and now Minassian too. One post, featuring Minassian as a profile picture, warned: “This is when we attack,” and predicted “at least 10 more incels will go normie hunting by the end of this year.”

Much of this may be just talk, but Rodger, and now presumably Minassian, have proven that some men will take their sexual frustration to the extreme. Meanwhile, the most hardcore “incels” will continue stoking hatred online, while blaming the world for creating the monsters they’re becoming.

Twitter: @BKEROGERS