iOS doesn't. Apps using private APIs are not allowed on the App Store. Apple granted Uber an entitlement for a private API, but no other app has this:
https://twitter.com/chronic/status/915930211941781504
App store validation == trusting Apple.
Because this was impossible without forcing users to stop using Objective-C. The language allows dynamic method dispatch and so it's always possible to allow internal API calls.
I don't think you're right; “entitlement” is a technical term used for OS-enforced permissions on Apple platforms.
I trust Apple a lot more than Google/Facebook/etc.
So I’m not sure why you posted that. Seems to undermine your argument.