One major problem is when people presume that their simplistic understanding of a subject is factual, and that everyone else is going off emotion. For example, some people will erroneously claim that the 2 genetic human options are "XX = woman, XY = man". Those seem to be the most likely combinations, partly because we don't collect DNA from 100% of the population and compare it to the observed anatomy, but they're clearly and documentedly not the only options.

Even without considering trans people, it's factually untrue that "XX = woman, XY = man, and those are the only possibilities." And yet, people who stopped at high school biology will argue until they're blue in the teeth that anyone with a more nuanced take is anti-science.

Yes and some people will also make scientifically inaccurate claims like "sex is a spectrum" and "there are more than two sexes" and "it is possible for humans to change sex".

There's a great deal of misunderstanding around this topic. Having open-minded, interesting and reflective discussion about topics like this should however lead to greater understanding. But that is not possible if it gets flagged and censored.