To be anal, the root cause of that is using javascript instead of building a native app.

I get that Facebook has the biggest apps on any platform and they run into platform limitations (like number of classes on Android) and build cycles so for them it makes sense to make a dynamic partial-hot-reloading-in-place app development framework, but they're still beholden to the runtime that Apple offers them.

(In theory they could compile JS to a compiled binary that Apple's reviewers are okay with, but I don't know enough about any of that)