Trans is an ideology, a belief that men can become women and that females should not be allowed to deny this.
I can see your point now you've explained it in different terms.
I think we are coming from different interpretations of trans (not just you and I, but lots of people on the thread).
If you treat trans as an ideology, as you have, then I agree with you, I'm not pro. I think it's misguided.
If you treat trans as a person, as I have, then I support their choice to live in the guise of the opposite sex, which is essentially choosing to adopt a gender role and dress code that society deems to be male or female. In that respect I'm pro.
You argue that is simply normal human rights, and it is, but human rights covers so much, it can be hard to figure which specific human behaviours are supported and which aren't. If someone is pro human rights, are the for or against abortion?, are they for or against anti terrorism laws? Etc.
But back to trans...
As well as being an ideology (as far as science cannot yet prove a cause), we still have people who have taken things a step further and undergone medical treatment to significantly modify their bodies into facsimiles of the opposite sex. We seem unsure of how to treat such people when it comes to spaces and specific rights for specific genders. Being pro human rights doesnt offer an accurate enough account of what level of support such people have. I think that is why people explain they are pro or anti trans, and go on to express the limitations of their support.
I guess they could just say they are pro human rights to dress and act freely, but stick to birth sex laws etc.