It had always seemed to me the (normal) YouTube video itself has no protection mechanisms applied, counter to the claim that's what the rolling cipher is about. Certain types of "protected" videos (movies, TV, etc) with Widevine and the like sure, but on normal videos there's nothing implemented for protecting the actual content from being captured or replayed. The rolling ciphers mentioned are implemented at the layer of and seemingly only for protecting the delivery because, of course, YouTube wants to be able to say 3rd party clients (which bypass any form of revenue and user behavior data they get for the cost of providing the delivery) are breaking their protections.
The video stream played in the browser does not have any such rolling cipher protections and it seems a stretch to try to argue recording the screen recording is bypassing what those are meant to protect, but it'll be interesting how the court perceives this here.
TorrentFreak's analysis here also isn't very good. This isn't a contentious matter where we're seeing two equally well-argued sides. There is no open question here or a novel defense strategy. The DMCA has statutory damages around the anticircumvention parts, even if the circumvention is in regards to enabling use that is not otherwise illegal. That's what makes it insidious. This guy is going to lose if he did use a ripping tool instead of a screen recorder and this is the defense they stick with and the outcome of the case is decided on its merits.