I doubt this will drive many users away. Most people just don't care. And most users' friends are in the same country so they'll still have consistent experiences.
What is happening here is that Facebook is banning the accounts of political leaders in other countries at the behest of the US and Israel in order to disrupt the organizing efforts of those leaders with their own people.
This has nothing to do with restricting what content is available in the US or Israel but is basically an act of war to disrupt the communications of a foreign enemy.
If somebody is on an American sanctions list, then Facebook USA making an account for that person on a database located on American soil violates the sanctions. That American citizens can't see the relevant account's data is irrelevant; if anything, it could actually amount to obstruction of justice if American investigators have a warrant to see the relevant data on an American server and it does not appear in the investigator's UI despite the warrant.
The way to solve that is to have different legal entities own different sets of data that exist under different sovereignties and then draw upon the data from each sovereignty through established (although potentially entirely private to Facebook and its foreign subsidiaries operating the foreign servers) protocols.
I'm sure they could make it redirect anywhere they want.