A while ago I had a very exhausting conversation with someone under one of my posts that perfectly summed up, why the TMA/TME binary is harmful. The person self-identified as TME and they have deleted their comments, probably because they realised that leaving evidence of being a bigot is not a smart idea, so I will have to paraphrase.
It started with the comment "lets not pretend like cis men are discriminated against", in the assumption that I was a trans man. I know that they assumed this because when I told them that it was "brave" to post this under the post of a cis intersex man, they became very upset and asked why I, as a cis man, was posting about the experiences of trans men.
I proceeded to tell them that I am talking about these experiences, because I have had the same or very similar experiences due to being intersex.
At that point they decided to tell me, that I was not actually cis then, but trans, and that I just didn't understand my own identity.
I had told them multiple times at that point, that I originally had been AMAB, and only reassigned AFAB to enable my IGM. This user was pretty much saying: trans means transitioning away from your AGAB, you have trans man experiences, so you are a trans man, so the doctors were actually right to reassign you AFAB. They were at this point agreeing with my abusers just because my experiences did not match their expectation of what experiences a cis man can have.
And that is the danger of TME/TMA and why it will never have any validity in my eyes. You are assuming the amount and type of oppression a person experiences based on their AGAB. And if that doesn't match up in your eyes, you assume that a) they are lying or b) that they are to stupid to understand their own identity.
They also half way implied that I no longer identified as trans because I was transphobic and not because I learned about circumstances of my birth and lifelong medical treatment that had been maliciously hidden from me.
The person later gave in and apologized, but then immediately invalidated that, by replying to another intersex user who came to my defense that "we don't get to tell them that TMA/TME is intersexist". A perisex trans person telling two intersex people what they are allowed to call intersexist. That is the state this stupid binary has left the trans community on tumblr. In the end users of this binary believe to have the authority over others experiences and identity. And that is fucking despicable.