I really do think it's a weird aspect to fixate on, though.
So long as Apple is only scanning the photos that're being uploaded to its servers, it genuinely doesn't matter to me where that scanning happens. It's a scan that could have happened in either location, and the version where it's happening locally is arguably more private/secure-from-fishing-expeditions. If I don't like that the scanning occurs, I can disable the uploading.
The distinction would matter if the local-scan involved things that weren't being uploaded. But it doesn't, so from my perspective the only difference is an implementation detail.
