You do not need to be able to do better to criticise someone especially if they are a big star who cannot sing in tune. I am not the one earning millions so I do not need to prove anything. Songwriting is just a hobby for me I just perform for a living. So from that POV I qualify to know a good song and a good singer when I hear it....I have always been my own man and like what I like not what others tell me to like or what others less discernable like. I am not swayed by the public's perception and their fashions and fads especially kids who are not musical and who are easily led. She is no diff to most of the other girls her age who post on YouTube I see nothing of any greatness in her tunes and her lyrics are nothing special even for a teenager there is little diff between her and Miss Rebbecca Black of the Friday fame......the one who wrote a song on Friday and was laughed at on Saturday.
Perhaps you have surrounded yourself with mediocrity so much that you too have learned to accept it as being something special.
I view music as a skill and an art form not from a business POV so perhaps the dollar signs blind people too much. Perhaps you are thinking more in dollars than taste and talent. Maybe that is why you get it and I do not.

http://www.soundclick.com/bands/songInfo.cfm?bandID=687727&songID=5238055