All valid points but then youtube is doing something that allows them to detect even derived work albeit they do have access to the full video so that might not work for everyone. At the very least with a registration based system it's clearer who "owns" what.
That's how copyright used to work, but they got rid of that after the Berne convention. Also, Google has some very fancy tech; it's not something just anybody could make work. And even they don't have it working all that great.
And then there's the matter of who has to bear the cost of creating and placing the filters, sites outside our jurisdiction that don't bother with those expensive filters, etc. You end up hobbling the US tech industry for no reason, putting everyone at a competitive disadvantage.
