Television journalism in the Sixties and Seventies was not as it is now. For one thing, you didn't have these all-news networks that needed incendiary talk programming to keep enough people watching to pay the bills. Same with talk radio, which didn't really exist to any extent.
No internet, either. No blogs. No news sites and all the entities vying for primacy.
The 30-minute nightly network newscasts all played it fairly straight and the Sunday interview programs, while edgy, were not as adversarial as we see now. They can get nasty now.
Things began to change noticably during the Vietnam War and then Watergate. Guys like Dan Rather and Daniel Schorr started insinuating opinions, but they were a little unique for quite awhile.
Now, even Colbert and Jimmy Kimmel are on every night stirring the pot, most of the time from right to left. But Johnny Carson, when asked why he avoided overt forays into political commentary, stated his belief in, and his intention to continue, the Jack Benny/Milton Berle template in doing his job, not the sardonic, cynical commentary model we see on late- night television now.
So lots has changed.