This is an invasion of privacy. I can understand Apple et al wanting to protect the integrity of their serves, etc. However, to be able to, to be allowed to invade individuals' phones is a not so thin end of a very big wedge.
There will be mistaken allegations, people's reputations destroyed, etc. Think of baby bathes, different cultures such as Japan were family bathes, indeed, communal public bathes etc are common.....
And of course, every authoritarian and/or dictatorial government will want the technology for their own legal purposes. Think China, Burma, Russia, Saudi, etc. As has been well reported, tech companies are experts at using the defense of "we must follow the laws of the country".....Does anyone seriously think Apple will walk away from the China market when asked to use the technology to find demonstrators?
Finally, how long before this technology will be everywhere in the Apple universe; iPads, desktops, MacBook Air, MacBook Pro.....?
My understanding is that this is like Google Pixels "now playing" - it is a downloaded local database of hashes of known pornographic photos of children, and it compares those to your photos that you are uploading to icloud photos. That's it.
If you take photos of you kid in the bath, unless you've already distributed those photos to people that have had them distributed to child porn sites and they have been found and hashed by Apple/the government, you're fine.
Don't distribute kiddy porn and you'll be fine.
In terms of google, well google already scan and index all the photos you upload to google photos, so you shouldn't be any more concerned about this news of Apple trying to stop kiddy porn.
If anything, Apple is actually behind the curve on this one. Microsoft, Google, and Dropbox have been scanning shared images on their cloud servers for years now to varying degrees of success.
I believe Apple is doing the right thing, a lot this initial uproar is because people don’t understand what is actually going on (which says a lot, because it’s actually nothing new), and that in time, it will gain acceptance.