Okay, let's start from the top: Vietnam. Kennedy saw we were in a no win situation. He had already had ordered a withdrawal of troops which had started the autumn of his death in '63. Johnson, upon taking office, immediately reversed that order. Fast forward to the Tet offensive, and Cronkite's comments that it was at best, a stalemate, but that it was unwinnable. It prompted Lyndon Johnson to say, "If I’ve lost Cronkite, I’ve lost middle America." And he was right. Less than a decade earlier, Eisenhower warned us of the Military Industrial Complex, and he was right.
Cronkite didn't pull his opinion out of his ass: he went into the field and got the story directly. As we've seen, the DOD fudged the numbers of US & Vietcong casualties to make it look like we were winning the war.
No, Cronkite was correct on Vietnam. He was correct to report the truth of the boondoggle our government and the MIL that Ike warned us about.
You point to an article where Cronkite stated that he did not believe there was a Soviet threat. He's not the first one to say that. Once tourism opened up in the USSR, Robert Heinlein and his wife visited the country. As she had learned to speak Russian, she was able to speak with Russian citizens about the state of their country. Bob also made his own observations. Smaller families were the norm, while the population was far from its pre WWII number. It's a good article and you can find it in his collection EXPANDED UNIVERSE, under the chapter "Pravda Means Truth"
No, Walter earned his title the most trusted man in America.
Oh, as far as the military budget, we spend more on defense than the next five countries combined. FDR showed how to use a military budget to improve the country in tes of peace, and to prepare for times of war. The later was an unexpected side benefit. We need to re uid our own country before we go off destroying others. But, that's another issue. One Trump would be better at achieving than Hillary.