So more scanning of arbitrary data for the sake of sanctimonious reasons, and definitely not for the sake of collecting data. I'm curious what is send where regarding those scans. There has been a scandal regarding amazon and those ring cameras. That software might run on the device, but whatever detection it's using is bound to make mistakes, and who sees the results? Is everything fully automated? Or human verified? I don't know which one would concern me more. Not even talking about young people taking photos of their body for various reasons. And just because it runs on your device does not necessarily mean that whatever is scanned is never sent anywhere. It just means that the scanning happens on your device.
Quite frankly, if it wasn't horrible i'd find the idea of some secret ring inside of apple using that CSAM-detection to collect material to sell on the dark net rather interesting. Might make an interesting plot for a thriller or novel...