“That’s not a slippery slope; that’s a fully built system just waiting for external pressure to make the slightest change.”
Apple will scan every photo headed for iCloud against a hash list from NCMEC, on your own phone. It will also scan iMessage images on child accounts. Apple says the scope is narrow. Widening it takes new machine learning parameters or a config flag, and governments like India’s are already writing the demands. Apple built the machine and is asking you to trust the settings.