Also, even if you enable ADP Apple can likely still read the vast majority of your messages in other people's default-non-e2ee backups. The bad default is the problem here.
"No, not like that." :O) But seriously, you can also just turn off iCloud Backups for Messages. (iCloud > Storage > Messages > Turn Off and Delete from iCloud)
> …otherwise they need to stop falsely advertising iMessage as a strong e2ee system when it literally uploads its encryption keys to Apple by default.
iMessage is E2EE, but iCloud Backup is not, which I understand is a distinction probably not well understood by most HN readers, much less your average consumer.
It's all Apple software on Apple software and Apple's responsibility to match user expectations based on the claims Apple makes. No reasonable person would expect that Apple intentionally retains the ability to decrypt the majority of iMessage communications given their marketing of iMessage as e2ee.
It's extremely common for Apple services to be encrypted in transit and on Apple's servers by default, and additionally also at rest when you opt into ADP (which is how you say "I want E2EE and understand the ramifications of that" in the Apple Cinematic Universe).¹ As you noted, for the average consumer, ADP² is overkill and therefore a terrible default.³
¹ https://support.apple.com/en-us/102651 ² https://support.apple.com/guide/security/advanced-data-prote... ³ https://news.ycombinator.com/item?id=43934995
ADP doesn't need to be default for iMessage to be e2ee. Keychain passwords are e2ee without ADP. So is health data. Even Memoji are e2ee in backups! And I believe they can be restored even if you lose all your devices, using the same technique Google uses in their system. Apple could literally turn it on for iMessage tomorrow using the same infrastructure. Every day they are deliberately choosing not to.