What do you think they should do?
The thing is, neither Apple nor Google wants a future where the only apps available are those that lie in the intersection of what is legal in 180 different jurisdictions. (I mean, Myanmar just blocked Facebook. What if they demanded that Google and Apple remove the Facebook app from their stores?) The alternatives are to have a different store for each country (do-able technically, but a lot of work, and I don't like it on freedom grounds), or to just say no to some countries' demands that some apps be removed.
Specifically Apple: You had the "1984" Super Bowl commercial. Are you now going to be on the side of the censors? Or are you still on the side of freedom?
Leaving Pakistan means shutting down their Pakistani App Store, so the app still won't be available.
(Someone could, say, put the app on the US store and Pakistanis might be able to figure out a way to get it from there... but they can do that either way.)
> ...The alternatives are to have a different store for each country
OK, I guess you don't know this yet, but that's the way it is and has been the whole time. Different laws, different stores. We already aren't stuck with the intersection of what's allowed in 180 different jurisdictions.
If Apple chose not to exercise totalitarian control over iOS users by making their App Store essential to installing software on iOS devices, then Apple would not have to collaborate with the totalitarian Pakistani government. Pakistani religious and ethnic minorities could distribute software through whatever covert channels they've already established to resist their oppressive government.
On Android at least, apps can be region-locked.