Internal documents can contain confidential business information that is of use to competitors etc. which it may be illegal or a violation of an NDA for you to expropriate and publish. Then it becomes a public exhibit of everyone attacking each other and defending themselves instead of people working to actually solve the problem.
Moreover, "a company" doesn't do stuff, its employees do. If you're the employee, the first person whose job it is to keep the company from doing dumb stuff is you. And there is a process for that. If you're the one responsible for it, you fix it. If you're not, you alert the person who is, then their boss if that doesn't work and on up the chain to the government until it gets fixed. If that process works then the problem gets solved without there being anything to create a media storm over, and if that process would have worked but you decided to skip it then you're creating a media storm over nothing.
Moreover, "a company" doesn't do stuff, its employees do. If you're the employee, the first person whose job it is to keep the company from doing dumb stuff is you. And there is a process for that. If you're the one responsible for it, you fix it. If you're not, you alert the person who is, then their boss if that doesn't work and on up the chain to the government until it gets fixed. If that process works then the problem gets solved without there being anything to create a media storm over, and if that process would have worked but you decided to skip it then you're creating a media storm over nothing.