“Defining ‘man’ and ‘woman’ with reference to particular kinds of bodies is biological essentialism.”
This is nothing more than an obvious misunderstanding of the term ‘biological essentialism.’ Biological essentialism doesn’t simply mean defining a group by a particular biological standard. If that were the case, statements like People with Down’s Syndrome are those who possess a third copy of chromosome 21, Diabetic people are those whose pancreases don’t produce insulin, and blonde people are those whose with hair displaying low levels of eumelanin would also be examples of biological essentialism – a bizarre conclusion! In reality, biological essentialism refers to the idea that an individual’s fundamental nature is determined by their biology. Statements like Women are naturally less intelligent or People of African descent are naturally more prone to violence are examples of biological essentialism. These are intellectually indefensible, morally reprehensible claims that are obviously distinct from statements like Women have uteruses or People of African descent have dark skin.
Of course, some transgender activists do consider womanhood to be a sort of fundamental nature that determines a person’s personality, and many go so far as to embrace actually biological essentialist theories about “male brains in female bodies” and vice versa. Therefore, it’s no surprise to see some transgender activists misunderstand statements that link womanhood with a particular kind of body; after all, if you think being a woman means being naturally predisposed to femininity, then statements like All people with uteruses are women do indeed sound like biological essentialism! But this is just an unfortunate result of the gender essentialism that defines so much transgender activism; once you strip away the sexist stereotypes that frame gender in terms of personal behavior, what once looked like enforcing biological essentialism simply becomes acknowledging biological reality.