I have a much simpler explanation. It’s because the united states is twenty six times bigger than japan.

In the United States, you can literally fuck off to the other side of the continent if if you piss off the people where you live. If your neighbors can remember you and hold a grudge, then they can ostracize you. In Japan, the cities are close enough to each other that there will be professional connections all over the place and you will not be able to escape your reputation.