How many people actually use the comments vs just consuming the content? Even if many people read the comments (which I doubt) the majority of the comments aren't insightful and don't provide any contradiction to the point of the video. I don't have any evidence, but I think this may even make things worse. Since many people like to be apart of the crowd if all they are seeing is everybody agreeing it could solidify their views.

Also, when it comes to TV and radio some shows have callers to the show. It does make it interactive and can provide alternative points. This appears to be falling out of favor though.