>That link does nothing to refute the fact that the vast majority of people are male or female, and differences in hormones / development / personality is not relevant to biological sex in this context (already accounted for by saying 'essentially' binary, and strongly bimodal).
Vast majority people fitting into 2 categories is not the same as binary. That's the problem I am adressing. Vast majority of people have brown/blue eyes. It doesn't make eye color binary. Bimodal distribution is not the same as binary, it's spectrum by definition. The problem with looking at sexes as bimodal is that some trait can be one side of spectrum, another - on opposite. Some people don't fit that well on the scale. As almost everything in life - it's complicated.
Development and personality are absolutely relevant in discussing sex differences and again they are not binary. Development doesn't magically stop once you leave the womb. It's not as explicit or obvious as reproductive organs, but brain is absolutely crucial in sex determination. That's why you get trans people. MRI imaging reveals that some parts of their brain are closer to the sex they identify as, not as their genitals. There is some research being done in estrogen receptor pathways:
https://www.sciencedaily.com/releases/2020/02/200205084203.htm
