You can disable iCloud backup.

Doing so right while activating a new iDevice is the way to prevent its private keys from ending up in iCloud, and so preventing Apple, or law enforcement, or some malicious hackers from cracking into your device.

Photos that users choose to upload to iCloud Photos do indeed get uploaded to iCloud Photos?

I'm failing to see the issue.

I think you might be tilting at windmills here. The issue is that the post I'm replying to claims that data never ends up on Apple's servers even though it does. Thanks for confirming that it does, though.

Am I supposed to be shocked that photos the user uploads to iCloud are on iCloud?

The results of the scan looking for kiddie porn cannot be read by Apple until the device finds 30 examples of photos that match known kiddie porn, whereupon Apple gets the decryption key so they can see which images on their server need review, and a human review is triggered to make sure there haven't been 30 false positives.

> Am I supposed to be shocked that photos the user uploads to iCloud are on iCloud?

I implore you to read the comment I originally replied in order to understand the context of my replies. Personally, I don't care what you're shocked about or not, as my OP wasn't directed at you at all.