While I doubt this actually happened, I'm still disturbed by everyone cheering it on absent any context that would make OP not look like a petulant child.
Quitting without notice doesn't require justification, fuck the bosses, whatever.
But for all we know, this manager had bent over backwards to stand up for their employees, or cover for them. Maybe this employee took advantage of that and was miserable to his coworkers. Those are just as likely as anything else, given that no further information was provided.
At least invent a backstory how this manager was dogshit or abusive, or the company was awful. Make us want to believe that you're not just someone with a persecution complex who's quick to anger and lash out.