It’s because Cronkite called the Chicago police “a bunch of thugs,” and he did it live, on the air. Well, that’s what they are! And that’s what he told his producers, who said he’d made a judgment, which was wrong, since it was up to the viewers to decide whether the police were or were not thugs. He countered that he’d made an observation, which is what they paid him for: to observe and report. They said he’d expressed an opinion. He said sometimes an observation is inseparable from an opinion.