Sorry, Jellyslice I'm still struggling to understand your point.
I can teach the beliefs of say, Hinduism, even though I have no experience of it in my life because there are holy texts and a tradition of stories that have been told and re-told that can be used to say with a high degree of confidence what the Hindu faith says about a particular life event or value.
Where is my reference point for telling children what gender identity means? I am expected to cover it as something that is protected by law, but what is it?
I will happily teach respect for anyone regardless of anything about them. Respect for other humans, the planet, animals etc. But here in a list of protected characteristics is something I cannot explain and which I am aware some would try to explain in a way that would undermine characteristics which are protected by existing law and/or would require resort to unhelpful and offensive stereotypes.
Ofsted wield such enormous power that for something like this to be included in their guidance is effectively a diktat to schools to teach gender identity and to teach it in connection with the law of the land. That is very different from teaching something in a religious studies or ethics class.