Journalists are entitled and indeed obligated to be bound to ethics just as much as the next guy. The argument that everyone is obliged to deliver to the public everything they know about everything, then we will get into problems very quickly. If you don't like someone's journalism, you are free to perform your own counter-journalism; investigate and publish your findings.

There's no necessity that every journalist must publish everything they ever learn just because some guy says the journalist should. If that's how you feel journalists should behave, hire a bunch of journalists to behave that way, and perform your own journalism and do likewise.