If your narrative can be derailed by pseudo-anonymous actors, you don't control the narrative.
The idea that I'm primarily disagreeing with is that Facebook, Twitter, et al. can be hegemonic in a user-populated space. I don't think they can. They can certainly exert large amounts of influence and constrain it, but it's not monolithic and they don't control it. Federation only makes that influence more invisible. It certainly doesn't remove it.
You're still replying as if control is binary. No, FB doesn't fully control the content on their platform. Nor does China fully control their media. But they still exert much more control than do distributed systems.
For the sake of argument, let’s say federated social platforms will not solve "digital privacy, digital harassment, and digital overpopulation,” what is your proposal to solve these “problems?” Are you suggesting everybody stay on FB/TWTR/IG/SNAP? Are you saying nobody should use the internet to socialize? I seriously do not comprehend the point(s) you are trying to make.
Just because not all problems can be solved with Mastodon, and the like, does not mean they are not worth pursuing.
Instead of asking why these problems are endemic to every platform, people just say "let's try silver bullet #24 so that we can keep doing the same pernicious stuff with a veneer of progress" and now you have several more problems on top of the ones that already existed.
Are humans in large numbers capable of interfacing with individual human beings without engaging in pernicious behavior? The answer, as anyone online in the last twenty-five years is a resounding no. Are humans in large numbers capable of behaving immaculately when it comes to preserving their own or their customer's privacy? Once again the answer, as anyone online in the last twenty-five years (and several decades longer if you include proto-business networks) is a resounding no. If you add progressively more humans to anything, does the output improve? If the metric is human satisfaction, the answer is no. If the metric is the rate of return in a Ponzi scheme, then yes, okay, you've got me there. The cause of almost all problems is solutions.
As far as social media goes, it's literally designed to use people to promulgate human-motivated pseudo-information for as long as humanly possible. It's not for "socializing" or "meeting people" in the same way that TV shows and movies aren't there for entertainment. It's to sell the viewer's attention to people that have anything but their interest in mind. Moving to federated enclaves is just further deregulating an already throughly pernicious industry.
The idea that I'm primarily disagreeing with is that Facebook, Twitter, et al. can be hegemonic in a user-populated space. I don't think they can. They can certainly exert large amounts of influence and constrain it, but it's not monolithic and they don't control it. Federation only makes that influence more invisible. It certainly doesn't remove it.