hey I'm the girl. yeah this *beep* who I've repeatedly seen being cruel to my donkey basically raped me, but oh I'm in love with him now????
oh yeah this same *beep* starts smashing up a bar and everyone else keeps dancing like nothing's happening. nobody goes like "uh hey dude, wtf are you doing"
is this just how people's minds work in france? what the hell was going on in this film.
I think Bresson was making a subtle on statement on modern life and how it affected a small town (what was at the time "modern" in the 50s/60s). The blaring portable radio is featured many times, with loud rock & roll. We see more cars, gas-fueled tractors and motorcycles, and less donkeys and carts. Gerard and his friends even seem to dress like a gang not too unlike something from Rebel Without a Cause and West Side Story.
I don't know for sure, but Bresson could be saying the rapid intrusion of modernity was changing the village for the worse. Those who did not appreciate the older ways, and were either too young (highly impressionable), too indulgent (the drunk who lacked control of his basic faculties), and too stubborn/sinful (the father) - they all do worse under this change.
The one good character was the young boy who grew up into a hard working student. Modern life and rapid changes did not affect him. He was too intelligent and well-adjusted, and was brought up too well to become corrupted. There was a wholesome sturdiness to him.
It's not so much modernity & technology = bad. The internet we are using now is technology. It comes with the good and the bad. Those susceptible to its "darker side" may not have been...too bright/strong/mature to begin with.
But to get back to what you were saying, I think those kids dancing and not noticing all that glass shattering is Bresson's way of saying all of those youngsters have been corrupted in some way. They dance zombie-like, numb to things around them. Maybe they're even used to seeing juvenile behavior every night, and it has become their norm.
And I see some parallels with today's world. Social media, cellphones, etc can be a wonderful thing, but at its worst, it can make some groups of people superficial, vain, mean-spirited and callous (like those French kids in the movie).