Depends on the type of concerts you go to. I've been to jazz shows that are not quite loud in that you can still talk to the person next to you without shouting, but the levels are still definitely in the damage-causing range. Rock and metal shows have definitely been getting progressively louder through the years, and maybe that's also the reason I see more people wearing ear plugs now.

Who are the people that want it so extremely loud?

A lot of younger people mostly. You may be in the minority who are already sensitive to loudness in the first place, but a lot of people like to listen to music at absurdly loud levels.