A lot of times stars seem to have certain problems that many of us "normal people" would seem to never understand. Then there are certain situations where everyone can relate to what is going on. This is where people start taking sides.
In this beef, there is an issue between Taylor Swift who is very close friends with Justin Beiber's-ex Selena Gomez. Taylor was apparently with Selena through it all. From the cheating allegations to their on-again-off-again relationship. It can be said she does not care for Beiber all that much.