There's no "hole?" The sideloading feature is the hole, and it's there whether the user wanted it or not.Sorry but that argument makes no sense. There's no "hole" with you to interact if you stay on App Store strictly. You have to at least download malware in order for it to affect you.
Also people keep forgetting that MacOS isn't locked like iOS and everyone's just fine...
And I don't understand why people keep bringing macOS. Apple themselves have said they're not satisfied with the security of macOS, and they are increasingly putting more restrictions on macOS. From the perspective of Apple, iOS is their ideal version.