I think that, on average, you are probably correct. More people prefer the current behavior over the opposite behavior, where instead of 'Not Interested' one would be forced to select 'Interested', or perhaps 'Add to Watch List -> Chill Music'.

But I'm not interested in an average case, and if given the opportunity to switch between a blocklist and an allowlist approach, I would do so frequently. Unfortunately we're not given that opportunity whereas I am given that opportunity in many other different cases, the 'Mark as Unread' button on e-mails and RSS readers being one such example.

Yes, same. EXCEPT there is new content all the time, and if you're like me, you'll probably never watch 4 of those videos because a new top pick emerged since.