> If someone thinks biological sex is binary, that shows they're uninformed. Like gender, it is essentially a point cloud in n-dimensional space - largely bimodal, but with a few other notable clusters.

Not really though - if someone has carefully considered this topic and still regards the sex binary as the most appropriate model to apply, it's more likely to indicate they are considering function over form in their reasoning. In particular, reproductive function - i.e. why we all have sexed bodies in the first place.

With this model, sex isn't just an assortment of bodily features, but is based on the reproductive function around which several related aspects of our bodies have evolved, with male and female being the two types of anatomical pattern appropriate to each reproductive role.

However, I do understand that to those who want to believe that sex can be changed through pharmaceutical and surgical interventions, this view of sex as a functional biological system isn't as compelling as the 'point cloud' model, which comes with the implication that if these points can be changed somehow, then sex is too.