For every bit of good that is born from YouTube comments, there are countless orders of magnitude more bits of bad. This hides the comments section below every video. Enjoy your videos in peace.
If you are a creator yourself and want to be able to get rid of comments on videos you watch while still being able to check comments on your own videos, try my companion script instead. It takes a bit of JS to tell the difference between your own videos and other people's videos, so a CSS-only solution doesn't quite cut it for that. See comments on your own videos, don't see comments on everyone else's videos. The only thing extra you need to do is not be logged out.