Don't be so cocky about Facebook, TRAs.
Facebook has many I mean, A LOT of GC groups that are private or even secret. I hobnob on these groups on a daily basis with the likes of Posie Parker yes, they could ban PP but she is still there under her real name Julie Birchhill, Venice Allen, Julia Long, Meghan Murphy, and a host of other very well known names. TRAs can't access these sites -- the gatekeeping is strict and we talk. We can say what we like.
The movement has merely been pushed of sight and that is always dangerous. It hasn't been erased. We are still here, not only on Mumsnet; it's just that MN is public, which is good, as newcomers have easier access.
But we have gone underground. Like the French Resistance. They tried to kill that off , too, and look what happened. It's what happens when you try to kill off truth. It never works.
BTW a suggestion made today on one of those groups: instead of saying Transwomen are not Women, we should say, Seahorses are not Horses. Over and over. Everyone will know what we mean, eventually, but you can't exactly argue against it.