I think you're mixing up two things.

(1) TERFs, who go by that name. They are by definition radical, which automatically raises questions about their mainstream legitimacy. That's the whole point of being radical. And the whole point of the name is reacting against something. So, okay, you've got them pegged. It's basically right there in the name.

(2) Feminists who exclude trans people but who don't themselves adopt the TERF label. This is a much harder case to make. On the one hand, there is a very conservative, generally bigoted group of people who are against everything, and people who are for some things are natural allies against wholesale regression. But there is also a case to be made that the amount of noise made about trans women issues like prostate screening for women and about not equating women with menstruation is subtracting a lot of focus from cis women's issues like funding for ovarian cancer research. There absolutely is a tradeoff here in terms of attention; there is only so much attention to go around. Indeed, I've seen trans women on Medium attack advocates and/or advocacy for (cis) women's issues because they don't also mention how the issue affects trans men or women.

In cases where the problems are of type (1)--Texas, maybe--then the two sets of issues are aligned.

But in cases where the problems are of type (2)--most of the U.K., for instance (though you do have the anti-rights reactionaries mixed in)--then you have to make a much better argument than you did. Mostly you just declared that certain feminists don't count because they don't try hard enough to exclude reactionaries.