Just catching up with this thread and the thing that struck me was how much of this argument is caused by limited vocabulary and misunderstanding.
Unpacking:
A says: "I feel like a woman, I am a woman"
B says: "You do not feel like a woman. You are a man"
B hears: "My sense of inner self clashes with my understanding of masculinity to the point that I must reject masculinity. This sense of inner self feels more feminine to me and seems to be how women must feel. I must be a woman inside. By extention this must also be how you feel inside. Inner feelings are much more important than physical shape so you must now accept that I am in exactly the same category as you for all practical and legal purposes."
B thinks: "You can't conclude that what you are feeling is what I am feeling, you only know what you feel. The categories of man and woman are generally limiting and ideally only ought to even exist to describe biological facts, with everything to do with how a person thinks and feels and believes being centred around their freedom as a person first, man and woman being descriptive of only physical shape and chromosome type." (This being expressed briefly as B's reply above)
A hears: "You do not feel how you feel. You are limited to conforming to masculine roles because being trans isn't a thing. Trans doesn't exist. You don't exist."
No wonder this is getting tense on both sides. Neither person is stopping to check what the other person really means, or clearly explaining themselves to check that their words are understood.
I of course don't know what is going on in other people's heads but I am pretty sure that B's perception of what A means is completely wrong - A is not denying that Trans is thing, is not saying that trans people don't exist or that people with penises must get on with being manly men. I acknowledge there may be some people who do think that way but the vast majority of feminists really don't.
We really need to talk about this properly, slowly, carefully and taking time to understand one another deeply. There probably are on both sides some actually unreasonable people, and some people who just don't have the capacity to take the conversation to a deeper level, that's part of the huge diversity of humanity too. However, most of us are probably reasonable people who have the capacity for a more nuanced conversation but are currently being prevented from having it due to all the shouting and name-calling.