The 1996 instructional guide for upstart reporters called The News Formula: A Concise Guide to News Writing and Reporting by Catherine C. Mitchell and Mark D. West is about how to be a real journalist, the sort we should all aspire to be:

Any display of bias, any interjection of the news writer's feelings or opinions into a news story, hurts the contract between a newspaper and its readers. When an author expresses any sort of opinion, no matter how mild or insignificant, it becomes extremely difficult to trust the fairness of the story.

No exceptions:

What, then, are reporters supposed to do when a public official tells a lie or gives our misleading facts? ... The newspaper should report the statement, without any hint of the reporter's feelings about truth or falsehood. If the statement libels someone, of course, the newspaper must be cautious, but in the vast majority of cases in which the reporter disagrees with something a source says, he or she should simply report the statement and let readers decide about its truth for themselves.