You did the right thing, confronting him! Now just don't buy any of his future material. Often times it isn't audiences who demand unnecessarily loud concert volumes. It can be the same people who demand stupid-loud mastered CDs or downloads: The artist themself, their management, their label. In the case of the concert, it can be the venue management or chamber of commerce demanding such loud volumes. Ignorance comes from many sources, not just the people in the audience. It can also come from the so-called 'authorities' - management, the engineers teching the event, et al.