On a post about Great Britains sex-based spaces laws that was painted as trans people being “banned” from public restrooms, I pointed out that they are not banned, they just have to use the ones that are for their sex.

Nothing incorrect there. 100% factually correct. Sex and gender are constantly spoken about as being separate things now, since sex is not changeable (despite what the person who replied thinks)
I was then permanently banned for “transphobia”:

Do they even understand what a phobia is?

Girl, you’re siding with someone who is being outwardly transphobic. This is not a good look for you.
FYI, no one is arguing about changing chromosomes. People just don’t talk about it because it’s not important in the arguments about sex in society. When you take HRT, your body doesn’t function the same because hormones change that aspect of your sex. When you get bottom surgery it physically changes that external aspect of what we call sex. Sex can be changed. To argue otherwise is just wrong and transphobic.