I came on to say something similar to what NiceGerbil outlined above.
The language bait and switch has been regularly used by a small number of transactivists, who have a lot of reach, and from there the new position spreads to the still small, but very politically loud, group of followers.
So when first the mantra “transwomen are women” was introduced, it was understood by all that it was not literally true. Then moves were made, such as introducing a gap in the word “transwomen” so the claim could be made that it’s not a compound noun, but an adjective and a noun, and that therefore we could imply that men actually are women. And suddenly we were no longer going along with a mantra we all knew was a polite courtesy, but with a false, but aggressively pressed claim that it was literal truth.
So it seems highly likely the next stage to be attempted is indeed to move from “this is a man, who now identifies as female” to “this is a woman who used to identify as male”.
Similarly on a different front, there was a clear demonstration this week (in the Lancet, of all places) of a different attempted language shift. There, they are attempting to move to a position where the word woman can only be used if it is being used in a way that potentially includes men who claim they are women, but must not be used in an article about anything that relates only to women.
(As an interesting aside, that insistence might be starting to backfire, as women have made the very reasonable sounding suggestion that true “inclusivity” would be to use “women and [list of other identities claimed by women]”. Though that formulation is, in itself, somewhat troublesome, it does subvert the men’s insistence that women should only be used when it includes them. This technique might also be used to reasonably suggest third spaces, not because we believe they are really needed, but because they are such a moderate suggestion that objections from transactivists to something so obviously reasonable give pause to those who are undecided.)
Anyway, after all that, it’s obvious, even on Twitter, that more and more people are objecting to these attempts to use language to achieve an end (as opposed to natural evolution in language as understanding changes). The alarming and frustrating thing is not that they are managing to carry their opinions into the wider world, because they’re not. It’s the fact that despite not managing to do that, these men have so much power that they are still allowed to do this, despite the ever increasing sound of angry, but logical voices pointing out the problems and risks their propaganda is creating.