Some people feel the term is outdated. They say this while parading around what to me seem oxymorons, like "non binary women" or "he/him lesbians".
When a lot of these people say they aren't comfortable with their gender, I notice they often mention things like clothes, makeup, hobbies. More generally, they seem to talk about gender roles- masculine and feminine- than something to do with their bodies.
Here's the fact of the matter. Bathrooms, pronouns, legal documents; they aren't referring to any of that. They're referring to what's in your pants, or if you have boobs, or grow facial hair. Most people, myself included, don't care if you wanna wear clothes or behave in a way assigned to the opposed sex (there are folks who do of course, and most of us here know they're assholes). But unless you're changing something about that, it doesn't warrent a change in your pronouns or documents or bathrooms. As much as my own rights are under threat, I can't help but sympathize with the folks upset with that, I don't wanna share the ladies' room with what amounts to a femboy or "metrosexual" either.
Sex is bimodal, and I use the term bimodal specifically. There are edge cases, such as intersex people, or those with hormonal conditions like PCOS. I would argue transsexuals, those like myself who seek to change or sex, are among them. And hell, actual enben who seek out procedures like gender nullification too. I don't take hormones because I want to be feminine. I take them to be as close to female as I can possibly get with the medical technology available. That's how I want to be seen, and treated. I plan on surgery to change what's in my pants. If I could get a menstrual cycle out of that, I would, and probably go on to have children (because infertility is another perk of transition).
I don't have anything against the sorts of people I'm talking about- I want to be abundantly clear on that. Same with those who say, dont want bottom surgery. My frustration is more with the terminology, because there is a delineation there that I feel is erased. People decry older terms like transsexual as "outdated", but I feel it's much more apt for my experience. I am transitioning to the other sex (or as close as I can). My gender has been constant all the while
I think bathrooms should be segregated based on gender, not based on sex. Or even better, not segregated at all. Cheap bathroom "walls" and "doors" are part of what makes builders build more bathrooms per building.