Isn't that a consequence of free speech?
What I was saying is that it’s justified if the benefit is to society. This is based on two principles that are pretty much accepted across the board as far as ethical systems go. One, you are part of society and there’s nothing immoral about defending yourself against harm. Two, societal benefits are in the macro so even if a company is only causing a little harm per person the amount of harm prevented adds up.
So in my eyes and in the eyes of most ethical systems publishing these documents wouldn't be justified even if Techcrunch gains more than Twitter loses. Unless there's information in those documents that would benefit society as a whole (or if Twitter was causing great harm to someone else and it would be stopped by revealing the documents)
However society is not a single entity, but rather a collection of individuals that can be affected by an event in different and often opposing ways. To some it may be beneficial, but to others not so. Sure the group that benefits may be in the majority, but to ignore the minority group and declare that to "society" the outcome was good is to ignore the different views and interests that make up a society.
Accordingly, you can only really use "it's good for society" if there's a clear benefit. Exposing a chemical company that dumps waste into a town's water supply is a clear benefit. As is making false financial statements in order to inflate your stock to the point where millions will eventually lose their savings. These are clear cases where a whistle blowers in justified.
But yes, as far as what's a clear case there is some judgment involved. As my old ethics teacher used to say Morality isn't a math equation it's an essay question.