I'm not GP, so I can't comment on where their line is, but for me the difference between Copilot and Apple Intelligence is that I can turn off the latter and never see anything about it again. Copilot, on the other hand, is everywhere and it's almost all universally buggy garbage, even when it's disabled.
I actually trust the Apple Intelligence, when off, doesn't exfiltrate my data.
Yea I respect that.
I too would not want any unprompted access to my files.
At the end of the day this issue is that we don't trust the OS and we cannot easily validate how it is designed to behave.
Oh yeah and even when you turn off preferences/settings/features in Windows, they mysteriously come back later in one of the unilateral forced updates, against your wishes.