You are correct in saying there is negative content in other music, but the point is did the other performers AT THIS FAIR singing songs of the same nature as the music you are pointing out.  Wouldn't be interesting if we heard that all the other bands that played sang appropriate music AT THIS FAIR. This would make a difference and your argument would not really apply to this situation.  Little kids do listen to the lyrics and most likely understand what is being said.  They may not be able to differentiate if it's okay behavior or not.  Anyway, who cares about hearing about his life during an event that is supposed to be fun and upbeat!