A tweet thread from Vox host Carlos Maza outlining several instances of right-wing YouTube commentator Steven Crowder making homophobic and racist comments about him has prompted an investigation by YouTube, the company confirmed to The Verge.

Maza is the host of Vox’s Strikethrough series — a show about media, politics, and technology. (Disclosure: Vox is a publication of Vox Media, which also owns The Verge.) Strikethrough often catches the attention of Crowder, who has published “rebuttals” to the videos. But as Maza’s video recap on Twitter clearly shows, Crowder’s videos routinely contain egregious violations of YouTube’s policies against cyberbullying, including repeatedly referring to Maza as an “anchor baby, a lispy queer, [and] a Mexican,” among other derogatory terms. Maza says that Crowder’s hateful commentary has resulted in “a wall of homophobic [and] racist abuse on Instagram and Twitter” from Crowder’s fans.

YouTube’s community guidelines state that content “deliberately posted in order to humiliate someone, make hurtful and negative personal comments/videos about another person, or incite others to harass or threaten individuals on or off YouTube” is prohibited. More than a year ago, YouTube also vowed to crack down on hate speech and harmful content.

But YouTube has been slow to act. Despite flagging multiple videos over the course of months, it wasn’t until Maza’s viral tweet thread last night that YouTube reached out to talk for the first time. YouTube’s team told him they were thankful for his help, and would investigate Crowder’s flagged videos.

In the meantime, Crowder has published his own video in response to Maza’s thread, defending his series as political comedy and disavowing any form of doxxing attacks his viewers might undertake. Despite clearly violating YouTube’s policies on cyberbullying, Crowder is claiming that Vox is attempting to have his channel terminated. The Verge reached out to Crowder for comment, but did not hear back by the time of publication.

“By refusing to enforce its anti-harassment policy, YouTube is helping incredibly powerful cyberbullies organize and target people they disagree with,” Maza tweeted.

This isn’t new for Maza. He’s been dealing with Crowder since 2017, when the YouTube creator first started “debunking” Strikethrough episodes. Crowder has used homophobic and racist language in videos about Maza since the very beginning, but Maza told The Verge it wasn’t until last fall that he began to feel the severity of Crowder’s videos. Maza was shopping when he got a phone call from an unlisted number. The voice on the other end asked his name, and then took a pause that Maza described as unsettling. Before the caller could finish his question (“Why do you hate—”), Maza hung up, scared.

He couldn’t even process the call before more than a hundred text messages spammed his phone, all with the same message: “debate steven crowder.” “I just started blocking numbers,” Maza told The Verge. “But my phone was basically unusable because it kept blowing up.”

“Even when I’m writing scripts now, it’s almost like looking over my shoulder thinking, ‘Is there a way to write this that will allow me to not get blowback for this?,’” Maza said. “This is how I used to act in high school when I was brutally harassed for being gay. I’m still constantly looking over my shoulder.”

But Maza doesn’t blame Crowder. There are always going to be bullies, he said. The only difference between bullies in middle school and YouTube, he argued, is having a principal or teacher step in and remove the bully from the equation entirely. They realize “one side is being the aggressor, that’s unacceptable, and they enforce actual penalties on the bully,” Maza said.

YouTube has previously said that eliminating hateful and harmful content is its number one priority. But Maza doesn’t see action against that goal. “It’s YouTube’s fault,” Maza says, “because they created a rule and realized that it was too risky for them to enforce it, and put me in the spot of publicly showing everyone my humiliation to get YouTube to care. They know better.”

“There’s no algorithm that’s going to fix this,” he said. “The only thing that’s going to fix this is smart humans saying, ‘We know this is what people want, and we’re not going to give it to them. We’re going to shut it down because it destroys the whole community when we let people’s work profit from bullying. I just wish they had the bravery to recognize that, and act on it.”