Maybe you should point out to that admin that the statement "exterminate all penis-havers" (a extremly hatefull statement toward a sex-based group, not a gender/gender-identity based one) would not violate that definition on hate speech, and that therefore that definition is quite clearly missing protection for sex-based groups (I choose a male example, as a female one might not get the point across)

Also, on another leaf, the admins don't do all the work of searching for subs and reasons to ban them by themself. Thats done by the likes of Bardfinn and Bardfinn's followers. The Admins alone probably just couldn't be bothered, if there wasn't some big figure with the conviction that cis lesbians having their own sub is hatefull in itself (just keep the sub itself free from clear hate. Without the Bardfinn brigade, r/biologicalLesbians would have never been banned)