I've seen on Youtube many informative videos on massacres and natural disasters where users don't vote objectively. Rather, they vote based on their emotions, which is why these videos always have a substantial proportion of dislikes. They dislike the event that the video talks about, but probably appreciate learning about the event.
The problem with emotional voting is that it screws up the website's trending algorithm. Not as many informative videos will rise to the top because they are getting so many dislikes. (Youtube probably has some advanced algorithm to combat this, however it is not perfect). How can we change this voting UI to make users vote objectively on a video's quality, not on what they feel about the content of the video?