So it's a bit of a long answer but I really watched it all unfolding in front of my eyes over the years. Starting from my late teens I noticed discourse changing significantly. It was often hard to find examples of trans men, as most trans spaces consisted of trans women. Obviously there is solidarity there, but we each have specific issues and a need to connect with others who are the same. There ended up being a large community of trans men posting on tumblr that became a really good space to make friends, seek advice, and feel understood.
Then I started to see posts like the gender gingerbread person, which I always found to be stupid but assumed was benign. Suddenly though, that was the only acceptable way to frame your history, and any talk other than 'I was always a boy/girl because of my gender identity' was internalised transphobia and biological essentialism. Next came the increasing dominance of abusive people like 'genderbitch', whose entire content was defined by a pathological hatred and jealously of women and trans men.
It was from there that concepts like 'transmisogyny' emerged. Now I would never deny that there are unique forms of discrimination targeted specifically at trans women. However, that concept was used almost exclusively to denigrate 'privileged' trans men, and the disgrace of us taking up all the space. No trans man was entitled to reclaim trans slurs (not that I would do that anyway), and a trans man could barely post a thing without first apologising in some way and committing to 'centering transfeminine voices'. At a similar time, the concept of 'binary privilege' emerged, which asserted that trans people who transitioned were privileged over and oppressive to non-binary people and those without sex dysphoria (who at this point were largely one and the same). The reality of violence, discrimination, and the difficulties inherent to medical transition were waved away with talk of how much worse things were for those who wore a dress on occasion, because no one respected their legitimacy.
Trans people who disagreed with any of these notions would be ganged up on, accused of every form of bigotry under the sun, and targeted for abuse and harassment. The result was that people either stopped interacting, or pretended to agree with everything regardless of their personal feelings. As a result, the only voices that then existed were those pushing this ideology. That also resulted in the next generation of young trans people buying into it hook, line, and sinker as the only legitimate way to consider trans issues.
I belonged to the group who largely stopped engaging, and tried to divorce myself from the 'trans community', who made me feel increasingly uncomfortable, especially as someone with experience of male sexual violence. However, I was added to a secret facebook group for trans men by a friend. I originally intended to leave, but it started out as a much more normal space with people just asking for advice on every day issues for trans people. Unfortunately, even that space was ultimately invaded by people, who whilst biologically female, pushed the same agenda. Around that time was then I began to see lots of campaigns highlighting how 'some men have vaginas' and 'not everyone who menstruates is a women'. I always felt deeply uncomfortable with that. My biological sex has always been a source of misery for me, and I have done everything possible to move away from it. It's not all that fun to then have it exposed to morbid public curiosity at every turn. The people who pushed all that seemed to have absolutely no respect or consideration for the feelings of people with sex dysphoria.
I remember one incident where one person in that facebook group actually made their true feelings heard, which resulted in a mass of comments from people who had also felt deep discomfort but had been afraid to air it publicly. It was in relation to one non-binary user, whose main activity up until then had been to post youtube videos where they discussed how much they 'loved their vagina and dicklet' and how hot men found it to f* them. They started a petition to take sex dysphoria out of DSM, which resulted in many people reacting in disgust due to both the erasure of it, and the potential impact that could have on access to treatment. Ultimately the post was closed because it was too 'toxic' and I left the group. The only people I interact with today belong to a group for post-surgical trans men, where my feelings on these matters are shared almost universally.
As to what I believe was the motivation behind all of this, I think it was to fulfil the aims of abusive people, who wanted to behave in a typically predatory male fashion without anyone being able to raise attention to it. If all you can say is that a trans woman is a woman, no matter whether they masturbate in public, walk around in fetish gear in front of children, or deceitfully remove a condom to try and impregnate unsuspecting trans men and women (all real examples), then it removes people's ability to identify and address male sexual violence. IMO that's precisely why the focus has always been on removing what it means to be a woman, because the trans people engaging in this kind of behaviour are invariably biologically male. I'm sure there are examples of trans men who have sexually assaulted others, just as there are examples of women who have, but the same distribution of offending exists. If anyone who says they are a woman is one, and if no one can define which organs are female, then how can you challenge this kind sex-based violence?