Why the hell do DJs insist on “loud”?

We had a case of being a tad loud, but people dancing, adults and kids. It was too loud for some already. One of my grandkids had headphones to cut the sound.

He turned the volume up, twice!

It cleared the dance floor, and half the people in the room went outside, like some mass exodus.

But the DJ had no clue and had to be repeatedly told to turn it down.

Now it is too loud yet again so I plan to leave.

Why? Why the hell do that?