'People who denigrate music that others enjoy are h

People who denigrate other people for the music they like are snobs. But saying you think some music is no good isn't snobbish, though it may well be unwise or plain wrong-headed.
............
'. It's pretty easy to tell the difference between lack of stage experience and lack of sufficient practice (or skill) to be able to play the song competently and remember the words.'

No it isn't much of the time. Inexperience makes people come to pieces sometimes.