... and are any of the reasons they give (or don't give) reasonable?
By "trans community" I mean trans activists / trans people who are activists, as a braod group. Obiously I do not mean every single person who identifies as trans.
(1) IMHO it seems to me clear that "validation" is a big reason. I am not sure how often this is said, but trans people, especially TIMs seem to want women's spaces for validation, therefore they don't want 3rd spaces.
(2) Predation / feelings of power. Never said, but it is clear that some people in the TQ+ community (and any community) have genuinely nefarious reasons for wanting women's spaces not 3rd spaces. In theory this could be a tiny number, in practice we simply do not know, nor is it women's job to have to take on the (at best) mental load of wondering which ones might be dodgy.
(3) Using 3rd spaces is "outing". For this to be valid it would require passing in the first place. It also suggests that TIMs believe that the right of a trans'woman' to be perceived as what he is not is greater than the rights of women to single sex spaces. I don't think that the right to change someone else's perception of you (not least from perceiving truth to perceiving a lie) is a right that I support.
(4) Practical reasons. Accepting 3rd spaces means accepting they have no rights to be in opposite sex spaces. They know that if it comes to it, most of the time, 3rd spaces simple cannot be practically provided so 3rd spaces in effect means TIMs in the disabled or the men's.
(5) They are not stupid. They know exactly how 3rd spaces would play out. Women and TIFs would be in the women's. Men would be in the men's. TIMs would be alone or in tiny groups in the 3rd spaces, perhaps occasionally accompanied by a hand-maiden friend of theirs.
(6) It's harder to claim victimhood in 3rd spaces. If they can't get what they want (access to women), then they're better off in the men's (where they can whine) or the disabled (where they can whine and pretend they care about disabled spaces being used by people who are not disabled, but claim that they have to do it so it's women's fault the disabled is used by non-disabled) than they are in 3rd spaces where the only whine they can possibly have is "but we want to get changed with the women" which is less of a sympathetic demand than some of their others.
(7) Chaos. The whole movement (TQ+, queer theory) is about causing chaos and destroying normal, nice, civilized society and family life. 3rd spaces end a conflict, and they don't want to end conflict. In contrast being allowed into women's spaces for good is an acceptable solution because whilst it ends conflict on paper in practice it doesn't - conflict will continue and they know it and want it.
Third spaces do no solve the "problem" (men wanting to be in spaces with women for a variety of reasons), and, if anything, they would demonstrate the problem as well (women don't want to enter spaces with men) thus undermining the entire incoherent men's rights movement further.
What am I missing? Are there other reasons?