Right now Apple says they only scan iCloud uploads. We can't verify that, but let's assume they aren't lying.
Why not scan your whole library? They can, they could make the argument it's to fight CSAM. I mean if you aren't uploading to iCloud because you're a pedophile, obviously we should scan your whole phone just in case. Think of the children!
You seem to be contradicting yourself. You have the option to turn off iCloud photos in which your phone will not scan the photos because there is no point.
> Why not scan your whole library?
That may very well be the case in the future, but nobody can say for sure. But even if they do scan other files on your phone, it's unlikely they will do that for files that don't sync to iCloud. If this bothers you, you can always just sign out of iCloud completely. You can still retain access to the app store and music subscriptions separately.
Right now Apple says they only scan iCloud uploads. We can't verify that, but let's assume they aren't lying.
Why not scan your whole library? They can, they could make the argument it's to fight CSAM. I mean if you aren't uploading to iCloud because you're a pedophile, obviously we should scan your whole phone just in case. Think of the children!