This might be true, but unfortunately a lot of trans activism plays directly and strongly into this impression of dishonesty and mental illness.

For instance, the following two points are often made in close juxtaposition, with no explanation for how to resolve them: (1) gender dysphoria is real, is severe to the point of being life-threatening, is medically recognized, and gender-affirming care is an effective treatment; (2) a person is the gender they say they are and it is transphobic to ask (personally or at an official level) for anything beyond their word.

Let's try this out in some other context. (1) Physical disability is real, severe to the point of making mobility difficult, is medically recognized, and special parking places are critical for allowing physically disabled people to retain access to essential services; (2) a person is disabled if they say they are and it is ableist to ask (personally or at an official level) for anything beyond their word.

If you see people who don't look disabled, without disabled parking placards, merrily parking in disabled spaces, you might think that the people are dishonest or mentally ill. Now, I recognize that there are arguments that the second situation has important differences from the first. But it's also profoundly unexpected. When you have a profoundly unexpected position, it's reasonable to expect extensive, repeated, patient explanation. Trans activism tends to offer vitriol instead. This feeds further into the impression (despite it being technically a logical fallacy to conclude this) that in fact trans people are just dishonest and mentally ill--otherwise, why not just patiently explain the situation again?

Now, some ideologues never were paying attention to that in the first place: they "just know" (i.e. hold the unfounded, evidence-free belief) that trans people are evil and mentally ill. For those people, it's true: there is no middle ground because they only recognize their own ground as valid.

The problem comes when one treats every example of expressed consternation as part of the war with evidence-unresponsive ideologues. This is exactly what I meant by "civilian casualties"--people who are just like, "Wait, what? If you have to have a certification from a doctor for a disabled parking placard, and you're required to show it, why can't trans people do the same?" often get extraordinarily hostile responses on social media, at least, which makes the evidence-unresponsive ideologues' claims seem all the more plausible. These people, at least if they're not personally attacked too much, might not accept every position trans activists take, but they might accept some and there certainly is a lot of room for middle ground. (Polling data consistently shows this, incidentally.)

You don't seem to have addressed any of my claims regarding CT and Marxism, so I'll skip that part.

I think you missed my point about deferring to reality. The point is that when you can defer to reality, you don't need vitriol. Not every disagreement can be resolved by such an appeal, because either it is a disagreement on principle for which evidence doesn't (directly) apply, or it is a disagreement on causality in systems that are too complex for causality to be clearly discerned. Politics is one area where both confounds are often in play.

On the other hand, I completely reject that the existence of people who will allow themselves to be arbitrarily badly deluded instead of accepting well-verified facts argues that deferring to facts doesn't decrease vitriol. People don't need to scream about holocaust denialism, for the most part. Historians present evidence, marginally sane people go "Oh, okay, looks pretty clear", and that's that. They don't need to scream about whether the earth is flat, or the moon is made of cheese, or that the iPhone 14 Pro Max is bigger than the original Motorola Razr, or that babies can learn three languages, or that aphids tend to have live birth rather than laying eggs.

There's a repeated mistake here about arguing against the extremes. Arguments aren't for the extremes, even if it is those who have the most extreme positions who are most likely to express their disagreements; arguments have power when targeted to the middle, to those who can be persuaded; the extreme that is in the wrong then ends up more and more isolated. For instance, I have long argued (in public venues) against creationists not because I think they can be persuaded (though very rarely they can), but because I don't want anyone who is open to evidence to be deluded by the nonsense creationists put forth while trying to rationalize their beliefs.

It is difficult for me to assess whether Joyce is rowing back or not, so I'll stay agnostic on that one. Nonetheless, I reiterate that it is not at all contradictory to acknowledge that there is both some plasticity and some determinism. "Rowing back" to that position would be a good thing, because it's (more) correct, at least unless you get backwards which bits are more plastic and which are more deterministic.