Why the hostility? It's not like they changed the name of the Black Sea to the Sea of Turkey. It's not a "fuck you" move. Just keep spelling it the old way if you care for some reason.
Because the attempted name change is being done purely to stroke the ego of a right-wing authoritarian nationalist strongman. Attempts by such people to remake language according to their whims should be resisted whenever possible.
> It's not like they changed the name of the Black Sea to the Sea of Turkey.
I'm sure Erdogan would do just that if there were any realistic possibility that anybody would actually follow it. The "Türkiye" name change is as much as he thinks he can get away with.