* iCloud Photo Library was not scanned for CSAM content at the time of the announcement, which Apple confirmed at the time.
* iMessage E2E encryption is not opt-in. There isn't even an opt-out.
* The "E2EE features" you might be referring to is Advanced Data Protection for iCloud Backups, which is not related to the iMessage protocol at all. You don't have any guarantees about what your recipients are doing with the data you send them, ever.
There is US law which is ambiguous about the requirement on data providers to check content for CSAM material, which many have interpreted to require a check. This is why every other major cloud provider does scan for the content.
> iMessage E2E encryption is not opt-in. There isn't even an opt-out.
This is incorrect. iCloud Backup escrows endpoint keys for "Messages in iCloud" to Apple every night in a non-e2ee fashion, which means that a non-endpoint has the keys, which means that iMessage is not e2ee.
Apple has real-time access to plaintext of almost every single iMessage that transits their service. The only case in which they don't is where both users either don't have iCloud Backup enabled or both users have enabled e2ee iCloud Backup.
* iCloud Photo Library was not scanned for CSAM content at the time of the announcement, which Apple confirmed at the time.
* iMessage E2E encryption is not opt-in. There isn't even an opt-out.
* The "E2EE features" you might be referring to is Advanced Data Protection for iCloud Backups, which is not related to the iMessage protocol at all. You don't have any guarantees about what your recipients are doing with the data you send them, ever.
There is US law which is ambiguous about the requirement on data providers to check content for CSAM material, which many have interpreted to require a check. This is why every other major cloud provider does scan for the content.