That's stupid, I don't get the hype either.
Basically it works like this..
Most people are "not" the media standard of "good looking"
So when they watch TV or see Photos of the so called "Beautiful People", they feel denigrated and insecure...
Now, comes Gangnam Style where the Protagonist is an Ugly Fat Minority... So the audience for which thinks, Oh well, if "he" could be popular, and definitively "COOL", so could "I"...
Thus they can more easily put themselves into the moment.. and feel as if their Outlook is great despite what they "look like"..
This is a major component of why such a huge following exist, because it's a hero that's NOT exceedingly beautiful, one who you can get behind, and NOT be lost to...