It doesn't really matter whether all images are uploaded, or just 1 in x (for large value of x), due to the Panopticon effect.
Apple now has the ability to encrypt the images before sending them to icloud, with a private key you own. Except that some percentage of images that match the CSAM fingerprint with their neural feature extractor will be sent to a CSAM filter on the server side (whose workings we don't have many details about)
This whole thing backfired on Apple entirely due to psychological effects, not because they are really doing anything more "panopticon" that they would already able to do now on their icloud storage (after all people are ready sending their photos to apple)
FB and Google will exhaustively analyse every single facet of your online presence and use your pictures to train their ML models for face detection and object detection.
Apple, on the other hand, even explicitly splits Map directions to segments so that they can't know where you left from and where you are going to.
Anyway how is your assumption make sense , Apple cares about children and about your privacy so scanning your images in iCloud was wrong until 2021 when something changed, what changed? does Apple cares more about children starting from now or they care less about privacy? or are they forced to do it?
Apparently they have not - They say facebook reported something like 20m images in a year, and Apple reported 250.
Eroded trust, sure, but that is mostly because they did a terrible job communicating it.
The whole point for this is to be a probabilistic filter, so that they need to run the real CSAM scanner on a subset of files.
You can fall into two camps:
a) apple should never ever scan my private images I upload on their cloud. b) apple can scan the images once they reach their servers.
If you pick (a), then clearly neuralhash shouldn't exist and you can argue against that on the ground that you want utter privacy. But you have to be consistent:every other cloud service that does scan the images server side should receive the same critique.
If you pick (b), then you must recognize that this additional machinery doesn't increase their reach to your private data, but quite the opposite, it allows them to implement e2e encryption for 99.9% of your content. You may argue that it's unnecessary and confusing and spooky and be afraid of the slippery slope precendent for other uses.