For social media users who are sick of Twitter, open-source platform Mastodon offers a familiar refuge. Its use of local communities, or “instances” that are connected through federation, allowed users to carve out smaller, and hopefully safer, spaces. When Twitter drove entire communities off its platform, Mastodon gave them a new online home. But a recent flare-up around actor Wil Wheaton has sparked concerns about how effective the platform truly is at acting against dog-piling and online mobs.

Wheaton deactivated his Twitter account earlier this month, citing the company’s decision to keep Alex Jones on its platform. He moved over to Mastodon, one of the only platforms to present itself as a viable, direct rival to Twitter. However, Wheaton says his time on Mastodon was hardly any better. In a lengthy blog post published earlier this week, he describes the community as treating him “with more cruelty, vitriol, hatred, and contempt” that those on Twitter.

The details around Wheaton’s suspension and subsequent decision to quit social media altogether are messy. Wheaton was already unpopular with some members of the LGBT community for his use of a Twitter blocklist that blacklisted many trans users along with harassers and trolls. Additionally, many have been critical of what they see as a failure to distance himself from friend Chris Hardwick following serious abuse allegations. As detailed by one Medium user, Amber Enderton, Wheaton’s past behavior has led some to feel uncomfortable or unsafe in his presence. The clear tipping point for Wheaton on Mastodon, though, was a “bofa” prank. (This is a pretty typical internet prank in which one user baits another to ask what the nonsense word “bofa” means, so the original poster can respond with “bofa deez nuts.” It’s sort of like the updog joke.) According to Wheaton, however, the prank wasn’t his only issue.

“I was harassed from the minute I made my account, and though I expected the ‘shut up wesley’s and ‘go fuck yourself’s to taper off after a day or so, it never did,” he wrote. “And even though I never broke any rules on the server I joined ... one of its admins told me they were suspending my account, because they got 60 (!) reports overnight about my account, and they didn’t want to deal with the drama.”

On Mastodon, founder Eugen Rochko wrote that he was unhappy with how the situation was resolved. “An admin was overwhelmed with frivolous reports about him and felt forced to exile him,” Rochko wrote. Unlike a service like Twitter, however, Mastodon instances are independent servers run by those who created them. In an email to The Verge, Rochko emphasized that he has “no personal power” over other instances; he simply offers non-binding advice. “Mastodon the software will investigate ways to help mods deal with large numbers of duplicate reports and blacklisting reports from dubious sources. mastodon.social will continue enforcing our anti-harassment rules,” he tells The Verge. “Everything is too recent to give you a more in-depth answer on that.”

On his blog, Wheaton wrote that while he respects the mod’s decision (specifically pointing to the private server), he doesn’t agree with it. “I think it’s deeply unfair, as well as rewarding abuse of a reporting system that’s meant to protect users, but it’s their site and it’s their rules, and I can’t say I blame them,” Wheaton wrote. “The people going after me were pretty awful, and I can only imagine that an admin would get fed up with them, too.”

Wheaton says that he’s “done” with social media, noting that online attacks and dog-piling are hardly restricted to a specific Mastodon instance or even Twitter. “I see this in the online space all the time now: mobs of people, acting in bad faith, can make people they don’t know and will likely never meet miserable, or even try to ruin their lives and careers (look at what they did to James Gunn),” he writes. “And those mobs’ bad behaviors are continually rewarded, because it’s honestly easier to just give them what they want. We are ceding the social space to bad people, because they have the most time, the least morals and ethics, and are skilled at relentlessly attacking and harassing their targets.”

The concern over Mastodon isn’t necessarily about one user, famous or not, but rather the structural design that allows many users to dog-pile on a single person. “I’ve said before that I think it sets a dangerous precedent on how a large group of people can mobilize to drive anyone off the fediverse,” wrote Rochko on Mastodon. “Mob rule is universally dangerous: Mods and admins must examine evidence and decide based on wrongdoing and danger, and not on how many times someone was reported.”