You’re probably referring to this:
It’s worth reading in full. Wheaton’s point is that he’s discovered social media in general is not for him. He’s not singling Mastadon out, just pointing out that it isn’t a perfect fix to the problems he’s encountered on more toxic sites like Twitter.
Mastadon is tempting to those (like me) who want Twitter’s basic functionality without its broken design, bungling developers and Nazi-enabling executives. A federated and more decentralised FOSS version of that functionality allows individuals and instance admins better control over blocking of other individuals or entire instances without losing the benefits of the network effect.
That said, as Wheaton points out it still has flaws that bad actors can exploit. I do think that he is a special case, being a celebrity who’s outspoken about politics and who’s routinely and unfairly mocked because of a character he played decades ago, but his criticisms are valid ones I hope the Mastadon dev community takes into account.
