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?

Yes, biological essentialism is a form of transphobia. Whether you understand it or not. It is the excuse behind the bathroom bans being pushed out by the UK and many US states, and it actually kills people. By arguing that trans women should be segregated from cisgender women and put in with men because they are “biologically male” you are promoting transphobia.