How could a company conduct itself in such a way, and still expect to retain a fruitful business?
As someone from europe, I sometimes don't know what to think of japanese work culture from stories like these. Regardless if it's real, I often feel as if I'm missing a lot of context.
As an italian, poor condition of agricultural workers it's a well known problem, especially in south Italy well they "hire" african aliens, sometimes working for 2 or 3€/hour
I'm not sure if black companies really suffer from a lack of business. AFAIK, Watami is still well in business despite being awarded the black company of the year award multiple times. They had a 26-year-old employee kill herself two months after joining the company with something like 140 hours of overtime. I think they also had an infamous ad on their website where a man with kind of worrying look to him was praising working for the company (https://livedoor.blogimg.jp/anico_bin/imgs/e/5/e5dbf3ca.jpg). I remember when Akiba's Trip the Animation actually decided to parody that particular ad when they had an episode about black companies (https://twitter.com/chocochip1126/status/832183431819784192).
Of course they are, but when you quit, it's you showing them the middle finger, not them trying to screw you over (unless they still owe you money, but cours there side with the workers usually... tbh. even too much sometimes).
I dare say that if such a letter were to be sent from a company in my country, it would be grounds for legal retaliation.
Why would you put insults into writing, in official letters no less?
Depends how your salary is, but typically you won't do anything. I have witnessed a friend being bullied in such a way. She had to find about £5000 to pay for a solicitor to help her with employment tribunal case. Such money is out of reach to most employees. Yes, she tried "free" help that is available, but those people were useless, especially the union. Those people were not listening and were interested in checking the boxes and following templates and they made it worse in terms of mental health as my friend started losing hope. I helped her find a solicitor and paid first instalment, without my help she would go nowhere. In the end the employer settled - covered the solicitor costs, damages and gave good references so she could find a better job. The bullying employee continued to work there and was not sacked. Her ex-work friends kept struggling but had no means to do anything.
That might be the exact reason they wouldn't put it in writing, but there are many "reputable" businesses in Europe and elsewhere with horrible conduct towards employees, with limited options to defend themselves for the employee without risking being worse off for the next career steps.
Sometimes they're just stupid. But I wouldn't be surprised if it was simply the case that it's what they do, it's what they've always done, and it sometimes works, so why stop now? And maybe it's normalized; maybe you go to the bar with some managers at other companies and they talk about doing the same things. If the average person in this situation just wants to move on, and get away as fast as possible, then maybe they're more prone to giving in to your demands than fighting back.
Aside from that, in Germany it's a common practice to get an Arbeitszeugniss. It's essentially a transcript from your employer stating how you performed while on the job. By law it's has to be formulated to be positive about the employee. Because of this, you often have to read between the lines to understand the actual meaning of the transcript.
Yes, there are common phrases used as codes. For example "made a highly competent job" -> very good; "made a very competent job" -> good; "made a compentent job" -> mediocre; "always aimed to make a competent job" -> really bad
As someone from europe, I sometimes don't know what to think of japanese work culture from stories like these. Regardless if it's real, I often feel as if I'm missing a lot of context.