I can see only two valid points in the preamble on that site and they are pretty obvious.
Firstly, many young people are damaging their hearing with ridiculously loud music at pop concerts, nightclubs and so on. Noise deafness is an insidious and irreversible disorder and is going to be a high price young people will pay in future years.
Secondly, it would seem to me socially incumbent on the maker of music to ensure it does not disturb the peace of others who may not wish to hear it. I do not see it as being my social responsibility to endure all manner of music involuntarily, at home or in public. In this context the actual type of music is irrelevant.
Both these points I unhesitatingly agree with. However, to attempt to align certain sorts of music with good or evil, beauty or ugliness , is to usurp the creative and aesthetic rights of the individual. In art these must remain absolutely free if civilisation is to grow and not stand still.