Huh, but it's Google and Apple operating systems that are the only ones that actually protect user data by sandboxing apps from each other so they can only access their own data?

It's the open source operating systems (and MS) that only protect the root account, because they're designed for servers or academic/corporate campuses and not personal computers.

If I install a program from a package manager on Linux, it has access to my whole home directory. If I install an app from the Apple App Store, it only has access to the files I specifically tell the OS to open with it.