The Proud Boys, a far-right collective started by onetime Vice Media co-founder Gavin McInnes, have been banned from Facebook and Instagram in an effort to crack down on hate groups.

While the group’s violent objectives have long been clear, the move to block them from social media follows the arrest of several members of the group in connection with a brawl in New York City earlier this month. Social media has been a critical way for the group to organize and recruit members. Twitter had banned McInnes from its service earlier in the year.

The ban comes at a particularly sensitive moment for social media giants, which have found themselves in the center of a socio-political storm. The massacre last weekend at a Pittsburgh synagogue followed a flurry of anti-Semitic posts by the shooter on the fledgling network Gab. Conspiracy theories linking Jews to the Sept. 11 attacks have circulated widely on Instagram, the New York Times reported on Tuesday. And the suspected mail bomber who targeted enemies of President Donald Trump became radicalized on social media, sharing and re-tweeting a range of hateful messages.

Leaders of the tech giants have tended to view content on their platforms from a libertarian perspective, erring on the side of protecting all speech instead of weeding out select content and being accused of censorship. But with their influence growing around the world, the law of unintended consequences appears to be asserting itself.

In Brazil, far-right president-elect Jair Bolsonaro got elected after his supporters flooded WhatsApp with incorrect information about voting times and locations and attacks on his opponent. Southeast Asia has been another area of concern, with countries like India and Myanmar seeing waves of false stories shared on social platforms, often with fatal consequences.

Business Insider had the first report of the Proud Boys ban.