Can we stop calling trans people by their preferred name??

I've been seeing a lot of transphobia recently as people who identify as trans themselves are not being able to legally marry their preferred gender due to the laws in their home countries, and so i'm wondering if we can stop calling them by their preferred name.

I'm not trans, so I'm not sure where this logic is going.

If they want to legally change their name to be a person of the opposite gender, would they be able to do it from their home country, or would they have to change to the legal system in the country they're from?