Honestly, ever since I grew out of my teenage prog snob/music elitist phase, I've developed a "live and let live" attitude regarding music. If, for example, some friends have bonded over their love for Nickelback or Justin Bieber's songs have helped someone through rough times, then who am I to take that away from them? I may not be into stuff like that myself, but I wouldn't wish they never existed simply out of selfishness.
Kids did that for me. I get a tremendous amount of joy from music, and to watch my kid have that bond with her music... I could care less that it's Taylor Swift, One Direction or Panic! At The Disco. In fact, I'm going to see Harry Styles tonight at Madison Square Garden with her and two of her friends. He does a cover of "The Chain" by Fleetwood Mac, and I'm down for that (plus I LOVE his song "Sign Of The Times").
Through those bands (and their covers) my kid now likes Queen, Fleetwood Mac and a couple other more traditionally classic bands.