He sang a rather loveual song dedicated to a 16 year old girl in the audience. I can see why they would think that's creepy. Britney would know all about loveual songs, though..
wait what wtf???
Well yeah Britney shouldn't be talking then considering one of her songs is "If You Seek Amy", an innuendo for spelling out "forget me"
http://trashlounge.co.uk/12083/demi-lovato-clashes-with-angry-reject-at-x-factor-audition-taping/nevertheless it was a sweet burn