> An unencrypted system-level backup doesn't mean that the program being backed up is failing at security.
iOS programs can choose how their data is backed up. iMessage isn't just getting its data stolen by iCloud accidentally. These backups are a feature of iMessage as much as iCloud. And besides, iCloud is made by the same company, it's not a separate entity.
> iOS programs choose how their data is backed up.
Well desktop apps don't. Would you say that no desktop app that saves its key can ever qualify as end-to-end encrypted?
> And besides, iCloud is made by the same company, it's not a separate entity.
I'm not convinced that's relevant to whether the encryption is end-to-end or not.
I would say that no app can qualify as end-to-end encrypted if a large fraction of users send their data to the maker of the app in a form that can be decrypted by the maker of the app, regardless of the reason.
It makes a big difference. If I print out the texts I receive, it doesn't change whether the texting program is end-to-end encrypted. The same goes for backups. An unencrypted system-level backup doesn't mean that the program being backed up is failing at security.
It's bad that Apple doesn't let you encrypt your backups properly, but it's a separate issue.