@scottjenson I want to push back on a couple of things. first, the idea that "this is the same reason we lost Black Twitter" - to me they aren't really comparable at all. This example you led with, is a person observing that Masto doesn't meet their goals from engaging with social media professionally. That's very different from the combination of access, lacking mod tools & culture friction that repelled early Black adopters and made bluesky the path of least resistance.
In fact, the post in your OP doesn't seem like a gatekeeping problem at all, to me. It sounds like the dude just didn't find the engagement he wanted here, and therefore chose to invest energy otherwise. Only an issue under the assumption that a space has to be for everyone (big assumption!)
if I said "yknow there's just not a lot of response on bluesky to my cranky too-online autistic anticapitalist ravings" would that feel like an accusation of untenable gatekeeping?