Reddit’s move against the group fell into the same pattern that other companies, including Facebook and Twitter, and domain registrar services, such as the ones that banned the white supremacy site The Daily Stormer in August, have taken to address violent content.

“I view this as part of that broader movement,” Danielle K. Citron, a University of Maryland law professor who has studied the phenomenon of online hate, said on Thursday. “That there are communities like Daily Stormer that we find troubling and call for violence, and we don’t want to aid and abet groups that call for violence.”

It is not clear when the term incels was coined, but the link between misogyny and violence against women has emerged on sites where incel communities gather.

Mary Anne Franks, a professor of law at the University of Miami, who has studied online abuse and harassment, said that when she read Mr. Rodger’s manifesto she was reminded of George Sodini, a Pennsylvania man who shot dead three women in Pennsylvania in 2009, leaving behind an online diary that detailed his loneliness and lack of success with women.

“These men got angry at the women that they see as depriving them of something they are entitled to,” Professor Franks said. “It was a trend in online forums, that they legitimately had a reasons to lash out,” speaking of Mr. Rodger and Mr. Sodini.

Last month, after Reddit initiated the broader policy to clarify its rules on what content was banned, the first to go were subreddits for Nazi, racist and white supremacist groups. The move to ban incels appears to be part of a wider sweep of subreddits that it has flushed out over the years, such as ones that encouraged people to covertly photograph women on the street, or one that promoted rape, which was banned for “inciting harm.”

“Whether it is on this particular ecoystem or alternatively within the alt-right itself, it is part of the online world that has been growing very rapidly,” Heidi Beirich, the director of the intelligence project for the Southern Poverty Law Center, said. “Misogyny is shockingly frequent to find on the web in these areas.”