Hum... Maybe you didn't notice all the frenezy, but you can't dislike something anymore.

I'm not a very active user, but I think there is no positive "don't show me stuff like this again" action you can do anymore.

The public dislike count was removed. Dislikes are still counted and presumably affect recommendation

You need to prune your suggestions by clicking the three-dot menu on the suggested item and "Don't recommend video". I started this last year and after a week my suggestions cleaned up and are absolutely relevant and high quality to my interests.