Unfortunately, the comments section is a cesspool for the worst anonymous trolling the Internet has to offer. You never know what will show up there even on innocuous videos. You also never know what filth might show up in the suggested videos.
It’s probably better to just get rid of all of it besides the actual video. clea.nr Videos for YouTube does just that. It eliminates comments, ads, favorites and suggested videos, leaving only the video.
clea.nr is a browser extension that loads into Firefox, Chrome and Safari. You’ll still be able to have all the player controls and share videos. Plus, you can unhide all that stuff with just a click.