People worry about kids playing with guns, and teenagers watching violent videos; we are scared that some sort of culture of violence will take them over. Nobody worries about kids listening to thousands - literally thousands - of songs about broken hearts and rejection and pain and misery and loss.

This quote is talking about how people are more worried about kids playing with guns and watching violent videos than they are about kids listening to thousands of sad songs. People are scared that the violence they might see can damage their children’s understanding of acceptable behaviour, but songs with lyrics about broken hearts, rejection, pain and other negative emotions appear to not have the same effect on children.