In the world of internet argument, people too often believe that if they have a point, their position is vindicated. But that is not always the case. Ms. Montgomerie makes the argument that trans women are safer in women's rooms than mens' rooms. But some cis women feel safer in women's rooms if trans women are not allowed in. Some of that fear is transphobia, but some of it is fear of bad cis men who will pretend to be trans because that will get them into women's spaces. That latter fear may be misguided, but, in the absence of long-term experience with rules allowing trans women (especially pre-surgical trans women) in women's spaces, one cannot be sure.
Either way, the fear of bad cis men is not "transphobia," much as people would like to label it such. Nor, given that there are bad cis men, can it be called bigotry. If protecting that fear requires that (pre-surgical, because that's really all this is about) trans women risk using men's rooms, then we have a conflict of political interests that results in someone not having a "right" to feel safe in the bathroom. That argument does not require that anyone "hate" or "fear" trans people, yet the "trans" side, perhaps lacking confidence in the logic of their postion, seems invariably to want to insult the women who fear bad cis men. I could call such a silly posture "pathetic," but I prefer the view that not everyone who disagrees with me is ipso facto scum. I commend that orientation to anyone trying to persuade anyone of anything. As if.