Surely there is is legislation to say how loud a rock band is allowed to play? If a factory owner exposed his staff to noise levels that damaged their hearing, people would sue his ass off.

Other than misguided machismo, there is no reason why a band needs to play at ear-shattering volume. It doesn't make the music any better. Having ringing in your ears for days afterwords may seem tough at 25 but is no joke in middle age.