Of course, accusations of public value to society are not libel in Japan. Everything is judged on a case by case basis.
But for companies? The closest thing would be protection under trade secrets if you're an employee or business partner.
However, in recent years, it has become routine in Japan to identify and punish employees who have leaked wrongdoings. In the evening news this evening, a government employee leaked information about a fraud, and the elected governor identified and pressured the employee, and the employee committed suicide. Public opinion is overwhelmingly blaming the governor, but the police and other authorities show no signs of acting. Despite this current situation, anyway, it is legally true that “even the truth can be sued,” and is this different in the US or in the West?
But you're talking about extralegal harassment and intimidation committed my authorities, which happens everywhere unfortunately.