Incel, the online community of “involuntarily celibate” men radicalized by their shared mistrust of women, has existed on the internet for years. But it wasn’t until Monday, when a man drove a van down a street in Toronto and killed 10 people, that many people knew of its existence.

What makes the attack different from many other forms of terrorism is that incel isn’t an organized militant group united by political or religious beliefs — its main grievance is with women’s ability to choose their own sexual partners. An explainer on the movement from our sister site Vox quotes J.M. Berger, an expert at the International Center for Counter-Terrorism in the Hague: “Misogyny isn’t new, and ideological misogyny isn’t new. Having a distinct movement that is primarily defined by misogyny is [fairly] novel.”

Being involuntarily celibate and being part of the “incel” community are different — plenty of people, of all genders, aren’t having sex who would like to. Yet incels see the idea of a female “involuntarily celibate” as an oxymoron; they believe that unless a woman is “severely deformed,” she can have sex whenever she wants.

A November post on the forum Incels.me gave a detailed account of the poster’s struggle as a “female incel” that begins with “Before you judge: no, I am not alone because I have high standards, it is not voluntary, no one has ever in my entire life shown any interest in me.” The rest of the thread is filled with posters calling the original poster a liar, a troll, a “vapid whore,” “lonely and unloved,” and “pig woman.” She was then banned from the forum.

It isn’t surprising that in a subculture where women are considered extremely shallow, stupid, and evil, women’s clothing is also deeply suspect. Incels see women as either “Stacys,” who are hyperfeminine, attractive, and unattainable and who only date “Chads” (muscular, popular men who are presumed to sleep with lots of women), or “Beckys,” the “average” woman. Women in general are also referred to in dehumanizing terms such as “femoids” or “FHOs (Female Humanoid Organism).”

One visual explainer describes a Becky as wearing “loose baggy clothing to hide small tits/flat ass” and needing to wear “super tight yoga pants to get a few looks.” She allegedly carries a “$5 backpack” and has a “nerdy bun” because she “thinks guys like the ‘natural’ look.”

Meanwhile, a Stacy has a “naturally curvy body” with “big tits and ass” that “give men instant erections.” She has “sexy, majestic long blonde hair,” her makeup is “on point” and she carries a “$2,000 Gucci bag” and “lives in luxury”:

In another iteration, Becky is a feminist who “will likely die [sic] her hair green, pink, or blue after attending college” and “posts provocative pictures because she needs attention” despite being a “6/10.” Stacy, on the other hand, again has “natural blonde hair” and “shows off body online because she knows she can make big money off virgin losers”:

If certain discussions on these forums are any indication, there are only two types of women in the world of incel, both of whom are white, thin, and attractive. But while incels seem to believe that the untouchable (and seemingly nonexistent) Stacy will never sleep with them, they feel as though they are owed attention and sex from Becky.

They’re also preoccupied with the idea of a sexual economy: According to the Red Pill subreddit (a term that comes from The Matrix but among men’s rights activists refers to the realization that society is actually sexist against men), some believe that 20 percent of men are having 80 percent of all sex, which means “for every ten girls who are getting laid this week, eight of them are fucking just two guys.”

They also say that the bottom 80 percent of men are “left to fight for the bottom 20% of females. This works out for about 70% of the males, leaving just 10% of the males to struggle for the bottom 10% of females, who only want access to the top 20% of males.”

In other words, incels see themselves as that bottom 10 percent, and view their celibate status as a mathematical problem that’s rigged against them. It’s clear that this fixation also translates into an obsession over not just the sexual privilege that more attractive people have, but the financial one — it’s precisely because of her looks that Stacy can afford to carry a $2,000 Gucci bag, while Becky’s stuck with her $5 backpack because her selfies aren’t as hot. It’s no surprise, then, that some incels have called for a version of “sexual Marxism,” or a system in which every person is somehow matched with a partner of a similar level of wealth and attractiveness.

Misogyny, both online or otherwise, isn’t anything new. But by grouping women by their attractiveness and personal style and transforming their philosophy into a math problem, incels are making it easier for sexually frustrated men to see women not as human beings with their own sexual frustrations, but as numbers. Which makes it even easier to treat them as such.