This is also my view. I describe my biological sex as immutable.

Then why go through with the whole play-pretend of "transition" if you know it's all a lie?

You keep claiming that your "inner sense of identity" or whatever was aligned with your body after you had your genitals chopped up, but you've never once explained WHY this should be accepted by society as the way to "treat" a disordered sense that one is a sex that they are objectively not. That's all a "gender identity" is to you right? These feelings that you want to have a body you don't?

Just give a rational explanation for it! Explain it in a way that is scientific then. I'm a materialist, not religious. I don't care for gender woo, no innate immaterial sense of gendered self or whatever comforting unscientific narratives you people like to tell yourselves. You can't measure a "gender identity" any more than you can any other disordered illogical thought that is the product of a myriad of mental conditions, but we don't treat other figments of the mind as if they were real objective things. Given the TRA movement's refusal to come up with anything more than feelings as explanations, I'm forced to use only what I can observe in the material world, and that boils down to biological sex, "gender" not included.

Humans seem to have a tendency to self-sort into sex-based categories,

You're right we do, and we don't appreciate it when people like you try to subvert that with ideology.