Im confused about this. You can change your gender (name, clothes, genetalia via surgery, physical presentation by hormones, surgery etc). You cannot change your sex. I honestly thought this was fact, not opinion. Is it not?
Surely that is miles away from saying people of one ethnicity are better than another. Surely it's more like saying people from certain ethnicities are more prone to certain conditions than others (eg sickle cell anaemia). Saying that you can't change sex isn't a value judgement like saying "white people are better than black people" would be.
On the other hand, I'm not clear about what maya did, barracking on about gender Vs sex on work time when you are meant to be doing a job, especially if it makes colleagues upset doesn't endear people to their managers at contract renewal time.