That seems to be the pattern, US visitors get only the stupid new name while visitors outside the US get the Old Name (New/US Name). It's consistent across Gulf of Mexico and Lake Ontario.

Except in Canada where we get the silly Gulf of Mexico sub-script name but Lake Ontario is labeled just that.

I still see only "Lake Ontario" on my end (from Canada).

I see Golfe du Mexique (Golfe d'Amerique) from France in gmaps, and golfe du mexique/gulf of mexico/golfo des mexico on the maps supported by leaflet (depending on the provider)

I (in Germany) get "Lake Ontario (Lake America)" too, as well as "Golf von Mexiko (Golf von Amerika)". Maybe so the AfD leaders don't tell on Google to their pal Trump?

The name hasn't even changed in the US. Trump issued an executive order about it, which has no legal power over anyone outside of the federal government. It's not a law, it wasn't passed by Congress.

Google's capitulation is purely out of a combination of fear of retribution and the desire to suck up to power due to greed.