The only answers the gender critical can give when problems are raised that show there is more to the trans debate than simply banning transwomen is that it's all the fault of men who think they are women. Which is a bit ridiculous and totally ignores women who think they are men. As for blaming women for supporting men when the question you are being asked is about a transman you think is a woman anyway, how can men possibly come into that? It's a woman asking a question about someone you think is a woman. The fact that transmen make the problem more complicated and less clear than simply men pretending to be women, and your prejudices don't provide answers to that area of the matter, is not the fault of the women pointing out the inadequacies in them. But I can see you would need to blame someone.
No. Transwomen present a threat to women. They want to enter our spaces, to compete against us in sport, to change the language in ways that erase us, to skew statistics in ways that mean that women, as a sex class, are not accurately represented, and muscle in on female-only events and those which celebrate womanhood. They are also, on the whole, larger and stronger than women, and capable of doing us physical harm, particularly when they remain genitally and hormonally as men. Transmen, on the other hand, do none of those things, and are not a threat to women.
If we were 'phobic' about transpeople, we would want both transmen and transwomen to be discriminated against/eradicated/whatever you think phobics would want; but as we are not transphobic, but simply trying to protect ourselves and our daughters/granddaughters, this is not our aim at all. Instead, we concentrate on situations in which we feel that we (and our female friends, family and comrades) are threatened and speak up then.