Why do we like doujin music so much, and why do tone-deaf people enjoy singing but dislike/are purely apathetic toward music? Furthermore, why do we dislike modern music so much, with the typical exception of indie music or music produced by our friends or compadres?

Example. I would never show this song to my family. It would be more horrifying than telling them I am a Nazi. It would be more horrifying than telling them 9/11 was an inside job or Tomotht McVeigh didn't do it. It would have catastrophic consequences the like of which Earth does not yet know. Why? Why is modern Man so repulsed by catchy tunes? Behold:

https://youtu.be/f7tMeBGxIw4