Well, I'm assuming that Youtube has some sort of a script to check if ad traffic is blocked, to detect ad blockers. Sure, you can write some extension which by-passes it, but then they can change their script a week later to do it slightly differently, to make ad blockers unusable again. Meanwhile for Russia, they have some sort of an exception, so that there can be no ad traffic at all, and you can still watch videos. And they maintain this exception themselves, so there would be no effort on our part.