> Who decides the algorithm, and do you really can believe they won't ever change it to serve other more nefarious purposes like suppressing dissent?

YES. That's the problem. Whoever controls it has that power. We don't want that. That's the argument against ChatControl: "imagine that those who get in power are against you, and imagine what they can do if they abuse this tool".

But saying that "a law enforcement officer may see a false-positive between a parent and their child and I find this insufferable" won't convince many people, IMHO.