Again I don't think these people have thought this far. If you have CSAM on your phone then clearly you must be a criminal, who cares how it got there /s

The entire rationale they seem to offer is - to quote the article - "these companies make trillions of dollars, they can easily implement this".

It's like saying that since Google makes trillions of dollars they can easily land on Mars, after all money solves all problems including physics.