Because Justin Bieber is an obnoxious douchebag whereas the PSY guy is humble and kind. Go watch any of the interviews that PSY has had he is so grateful for what has happened to him with this song. Go look at the recent meeting Justin Bieber had with the PRIME MINISTER of Canada. The kid is fucking retarded.
So your basis on the quality of music is how nice a singer is. You must LOVE Gospel music then.
I describe myself as a little dose of toxic masculinity.