@futurebird I don't think "control" is enough to make a platform more positive for movements like this. I think some of the growth and virality that was possible and achieved for these movements relied not just on the size but also the architecture of these sites.

Famously (there's... some paper explicitly about this), the BlackLivesMatter hashtag (and people organizing within it) started on Facebook, not Twitter -- but it grew into a movement on Twitter.
(Likely, and I believe (which is why I'm bringing it up) because of the architecture & resulting dynamics of the platform as a social space (I think the paper also argues that), but it's also possible that the demographics of the platforms (or their role in the media ecosystem? but that feels like it's not NOT "architecture", maybe) also had an impact. Or maybe not, I don't know enough to say likely or anti-likely in either direction here, hopefully the paper covered it I don't remember it's been years.)