Looking at Glosswitch's post, she is making a point about how the purpose of women's rights is to look at the position of women globally, and to try and do something about. So it isn't acceptable to say that gender is just wearing a floaty scarf when for other women gender is about being denied essential resources, health care etc.
I think the same should be said about transgender rights globally. If trans rights are global, then it cannot be defined solely on the basis of trans definitions in a couple of countries (US, UK etc) as a fluid spectrum that is self defined from internal identity that is independent of sexual orientation and biological sex, because that isn't how non binary genders work globally.
There isn't any society with non binary genders, as far as I can see, that doesn't also make a distinction based on biological sex. Some non binary genders are chosen by the individual, with others being given by society based on birth order or perceived beauty during childhood. Some genders are given exclusively to subsets of males or females within a binary. Some are given based on biological sex and sexual orientation together. Some are given based on whether or not you have been pregnant and breastfed but no longer are. Some are a religious role. Some are based on being expected to do child rearing tasks. So in our own society the nearest conceptual categories we have for transgender people in other cultures are not trans people as understood by trans activism in the UK /US, but effeminate gay man, empty nester, maiden Aunt, rent boy etc.
I don't know how trans rights should be dealt with globally, but the focus must be on those in non binary gender roles globally. The pretence that non binary gender is an innate identity with no basis in biological sex or sexual orientation, and that it is a liberating force that breaks down an oppressive binary is damaging to non binary people globally. How exactly, is a society set up into three genders, where attractive boys are selected during childhood and told they are now lifelong members of a sex class relative to all other men more liberating than a gender binary? I don't see how the number of genders changes the likelihood of a system being more or less coercive and oppressive. The job of trans activism should be to represent trans people globally; I can't tell them how to do that.
If people in the UK want to take on identities like gender queer etc, that is entirely their business. Claiming that this is an act that will liberate the whole of society from gender is my business as well. Denying that such identities replace rather than exist alongside sex roles is definitely my business.
I can see that feminism is, in some instances, solely about female bodied people. I can also see in left wing terms that while women are placed in the reproductive class, there are some societies where third gender people are also placed in the reproductive class - assigned to do much essential care of children, to be sexually subservient to male desire, to clean, deal with sanitation etc on the basis of sexual orientation, innate aspects of physical appearance etc. In that sense, I would then view those people as politically the subject of feminism, because I'm not a radical feminist, I'm just a generally left wing feminist.
So I would include any third gender groups globally who are entirely within the reproductive class within my personal perspective on feminism and who feminism should be about, because feminism to me is about the reproductive class. I do not see that any trans groups collectively in the UK are part of the reproductive class. I also don't expect radical feminists to have the same view, because they have a different perspective and that is fine.