I think a popular video will attract votes one way or the other. A video that makes people angry will encourage people to dislike the video, and thus eat into

I think a popular video will attract votes one way or the other. A video that makes people angry will encourage people to dislike the video, and thus eat into the total vote share. I agree that this likely only covers videos with a large number of views (~millions). There's a long tail where the view count/vote count is not enough to comment on the number of dislikes.