I’ve never personally seen the kind of “dislike harassment” you are talking about. There was the YouTube rewind video a few years ago but that became more of a joke after a while.

However, I would not be surprised if this feature was accelerated after seeing twitch “hate raids” a few months ago. These definitely are a form of online harassment in my opinion. In YouTube’s competition with twitch they want to show they are a “safer” place for creators (whether someone believes this is up to them)