Ambient crowd noise before the music starts is ~85dB inside a venue (not to mention festivals), which is ~10dB above the acceptable limit for permanent hearing damage. The loudness, to some extent, is a necessity. That being said, I've noticed diminishing returns from a ~100dB show to a ~110-112dB show.

Street fests are the worst since you have a perfect combination of amateur sound engineers, outside sound shaping, and an amateur audience to boot. Sometimes I think bringing children to steet fests should be illegal if there's going to be that loud of music. I've seen some clock in at ~115dB! Ridiculous.