“Policing transgender women just makes it easier to police other vulnerable women, like lesbians and women of color.”

This objection is perfectly backwards. First, it’s totally unclear what “policing” here is supposed to mean. Presumably, the transgender activist is referring to those who choose not to validate a transgender person’s stated identity. But this isn’t “policing” anything – it’s merely holding to an objective standard for a particular social or biological category, which is essential for those categories to have any meaning whatsoever. In other words, disagreeing with a male person who claims to be female is not “policing their womanhood” any more than disagreeing with a married person who claims to be a bachelor is “policing their marriage status.” Words have meaning, and recasting a basic commitment to consistency and coherence as “policing” is absolutely bizarre.

Moreover, it’s unclear how standard for womanhood based in femaleness could pose a unique risk to women of color or lesbians unless you think that women of color or lesbians are somehow “more male” than white or heterosexual women. Most transgender activists would deny that they feel this way, of course, but it’s hard to explain what other attitude could be motivating these sorts of objections. Meanwhile, anyone who believes that non-white, non-heterosexual women are equally female (an indisputably obvious position) should have no reason to worry that excluding male people from womanhood “opens the door” to excluding anyone else. Quite the opposite, in fact! Grounding womanhood in a shared femaleness makes it harder to artificially exclude vulnerable women based on their race, sexuality, ability, or any other arbitrary factor unrelated to their existence as female human beings, whereas shifting to an identity-based definition of womanhood does exclude the billions of woman on this planet disagree with or are simply unaware of the gender identity framework.