Yes, it comes from real experience. And I hope you’ll ponder a bit why you doubted that it did.
There are many cis women who unfortunately are deeply invested in the idea that only women can be victims. And lots of transphobic women who appear in moments where a trans assault victim is discussing their assault, who use that extremely vulnerable moment to “remind” them that their gender isn’t real. Any time I write about assault I get inundated with comments like that, and it happens in real life too.
Not every cis person becomes hostile on that level, of course, but many do, and many others become dismissive, and don’t trust me to accurately describe my own experiences. Then they either ask a ton of questions in hopes to pick apart my understanding of my life, or they brush off everything I say and keep calling me a woman.
And when I complain about it, I’m expected to be the bigger, more patient person who tries to understand their point of view, and to be tolerant of their mistakes and misgenderings, and to explain to them why their understanding is wrong. I hope you can see how that might be just as grueling as explaining to people over and over again that a rape was actually a rape.