We use them interchangeably. You don't ever need to know someone's assigned sex unless you're their doctor so it doesn't matter, we are always talking about gender. Using a country where trans women are killed to claim oppression happens on the basis of sex makes you an obvious bigot.

Yes, language usage has changed and this has spread to discussions of pet animals also, which was my main point. Sorry, I'm not sure which country you are referring to, and what the claim about oppression is about?