All well and good, but FFS, you're not '70% man and 30% woman'.
Bear in mind that they've taken several short quotes with no context. My impression from having read his thoughts a few times is that when O'Brien talks about being both male and female he's talking solely about gender. I've heard him lament the stricture and prevelance of gender roles quite a lot; if he were a yoof he'd call himself non-binary. I don't think he's as precise in his language as feminists have to be.
This lead a lot of Genderists to assume he was One If Them, so when he pointed out that being Gender Critical does not mean denying biology they saw it as a betrayal in the same way as lefty women are 'betraying' them.