If you choose to use iCloud to store your contacts (and you can choose any other service that implements the carddav standard) Apple declares the information is transmitted and stored encrypted and can’t be used for any other purpose.
iMessage can be MITM’d by Apple when requested by the government and you, the user, will have no way of verifying your correspondent’s public key (unlike whatsapp, signal, keybase etc).
it’s probably nothing to do with USA law enforcement. my reasonable guess is they don’t care much and would go full private. i think the reason here is china. that way they don’t have to have a separate china policy which would draw undue attention to that point.
No, what is constantly being brought out as a huge negative when talking about Google and Facebook is them using your data and data about you to make money.
If you do not want this to happen, do not turn on the optional iCloud backups.
But anyway, although Apple could decrypt the other data, they declare they don’t. Which is what the labels are about.