I don't think that I've met a single cis person who uses the word "Transphobe" on a regular basis, who isn't actively and consciously engaging in self-deception.
There's no way around the fact that so many cis people who fancy themselves allies will say "trans women are women." and then completely melt down the second that they're asked to define the words that they're using.
Still, it goes much deeper than that.
I think it's safe to say that most of the aggressive activists on this issue come from a collectivist mindset. I'd have to be blind to not see the overlap when it comes to people who will call Thomas Sowell "Uncle Thomas" because he doesn't think the way that cis, white, leftists think that black people should think and the cis, white, leftists who turned on Caitlyn Jenner and won't listen to Blaire White, Buck Angel, or Marcus Dib.
There's no possible way to be an intellectually honest person while yelling "Transphobe!" at people who challenge the idea that we should be giving drugs, even surgeries, to people who are too young to legally get a tattoo. Some of these people won't flatly condemn the practice when it comes to kids who still believe in Santa and the Tooth Fairy. There are large swaths of people in the trans community who condemn these practices on minors with good reason. But, most of these so-called allies won't listen to that swath of the trans community. Those trans people don't matter to them. The so-called allies have to pretend that those trans people don't exist; or, they have to pretend that those trans people are the trans equivalent to self-hating Jews because, how could these trans people see nuance? It's not hard for me to understand, because I'm not a bigoted monster. Apparently, it's hard for illiberal Leftists to understand.
In the case of KC Miller, most so-called allies are still insisting that she's speaking out against all gender-affirming procedures. She's not. She was simply talking about the damage that was done to her as an individual -- and as a legal child -- that she can't come back from. Anybody who has listened to Miller and is offended by what she has to say is either lying or an evil person who doesn't acknowledge that kids lack the capacity to consent to life-altering procedures. To these maniacs, there's nothing wrong with telling a thirteen-year-old that he or she might want to think twice about getting a tattoo; but, it's bigotry to tell the same kid that he or she might want to think twice about being sterilized or altering his or her body.
How can this make sense to anybody with an IQ above room temperature? I'm not seeing it. These people can't accept that there are trans people who are happy with their transition -- but, they wish that they could still have kids. They have to bury that. They have to accuse people of bigotry for bringing up nuance. It doesn't matter if you've never expressed hatred for any group of people. If you treat trans people like human beings, the cis, white, leftist "allies" will accused you of bigotry.