[johnnyanmac]

You do need to take care in pruning videos you don't normally watch. Either remove from watch history, mark as not interested, or just thumbs downing the video.

But at least you still have that ability compared to most platforms.

[ChoGGi]

Isn't the thumbs down only from a third party extension? Does YouTube recommendations pay attention to it?

[johnnyanmac]

You can still thumbs down a video. You don't get any feedback nor metrics from it, but you can still do it.

I haven't paid close attention to the effects, because I don't thumbs down too many videos. But it did feel like I generally don't get that channel as much after thumbing down a video from my recommended feed.