There have been some interesting points sure but it seems like there's also quite a lot of hatred and disgust for anyone transgender, and willingness to support anyone who opposes "them."
Please stop projecting. Saying "no" to men who want to apppropriate and redefine womanhood, no matter how genuinely felt, is neither "hatred" nor "disgust".
It is simply saying "no" to men.
It is ok to say "no" to men even when it makes people sad.
In fact, a significant element of Feminism is learning, not just intellectually in theory but actually, in practice, that men's sadness at women saying "no" is not in fact, despite the number Patriarchy has done on us, women's fault, and nor is it women's problem to solve, but men's.
We get this soooooo much you know. Soooo many posters tread exactly the same path as you just have.
.1. "You surely wouldn't stick to your values if it made someone sad though would you?"
.2. "I don't have to explain why trans people feel how they do or why it shoudl matter more than sex, I just know they do and that should be enough right!"
.3. "You are all horrible people for expecting me to explain and I'm leaving this thread!"
But you know what I think is extreme? The idea that something in a man's mind - a man's mind - can be considered more important than women's reality. The idea that some men are in any meaningful way, in any way that matters outside their own head, somehow actually more like women than any other man.
So my reasonable position is this. I will accept that a man can feel so different to other men that using the language of men for him is hurtful and negating. And I will use any neutral or neo-language he wants to recognise that. But I will not go past that middle ground into validating whatever disordered ideas about womanood he is projecting on to us by using cross sex language for him, because that goes beyond how he sees himself and other men into how he sees us, and it is belittling and negating of us to accept it. It is not a reasonable thing to expect.
The middle ground is not "pretend he's a woman sometimes" - the middle ground is "allow him to differentiate himself from other men".
Oh, and by the way, "I also don't see why it's up to me to come up with a definition"? It's up to you because you said to me: "I don't agree that that's a universal definition of transgenderism for starters." So y'know, I'm kind of waiting for you to tell me what definition you are using, and explain how it doesn't just boil down to "how a man believes women feel, think or act is more meaningful than body sex".