I agree. Having this added to CoCs is a method of trying to enforce compliance to a controversial ideology.
Those of us who reject the idea that women and men are to be redefined in terms of "gender identity", and consider this to be a sexist belief system, either have to pretend to hold this view or be excluded from participating.
We do have studies showing this, and the research has been attacked in the way you describe. Far too many people have immersed themselves in this belief system, believing themselves to be righteous above all else, curtailing any critical thought around that topic.
It's kind of fascinating to observe once you realize what's going on, that it's a secular cult whose followers don't even notice they're trapped within.
Those of us who reject the idea that women and men are to be redefined in terms of "gender identity", and consider this to be a sexist belief system, either have to pretend to hold this view or be excluded from participating.