Does "the blue" refer to the police?
What is Deblasio? Bill de Blasio, the mayor of New York City?
If I'm trying to listen for that specific phrase, right around 27-28 seconds into the video something like "I can't breathe" might be in the background noise of the restaurant. But it's hard to be sure.
If I was not deliberately listening for that phrase to see if I could hear it in the video, I'd have never have noticed it at all.
To me that sounds like they are chanting "back the blue" which would be a chant in support of the police.
why are you laughing?
do you imagine them applauding and insulting them at the same time makes any sense?