Is Japanese work culture really that bad?
Black companies specifically, yes. People literally die there. Karoshi happened so much the government started publishing a shitlist of known black companies in the hopes of shaming them into compliance with labor laws. Of course, that never worked. Black companies still kill people and scare everyone else into staying with the threat of lawsuits and the thin hope that those fuckers might someday pay the days of unpaid non-overtime wages (because of course they often fuck their employees out of that, too).
More generally, Japan has an extremely unhealthy workplace culture, though there has been public backlash as of late. People stay at jobs for long hours, often working tons of overtime, to do... nothing. Nobody wants to leave before the boss, and the boss wants everyone to be at work so his employees look industrious. Much of Japanese culture is about
face, and maintaining that often means overtime spent spinning wheels until some nebulous good-enough-hour has been reached and everyone can go home. Nothing is actually achieved with these pointless daily rituals of playing pretend, but the overtime hours give the HR goons impressive numbers to hand over to C-suite to keep those parasites happy.