I think that NortherFront has a point, but is not making it well (sorry, NF - I agree with your premise, but not your supporting evidence).
The media DID turn public opinion against the war. And, they did it by reporting mainly the bad stuff, not the good stuff, and even by coloring the good stuff so that it seemed bad.
The biggest case-in-point was Cronkite and others reporting on the Tet Offensive. But any military measure, the Tet Offensive was a massive defeat for the North Vietnamese Army and Viet Cong. They attempted to strike South Vietnam towns, were repulsed, and slaughtered. They lose more ground than they had at the beginning, not to mention losing thousands upon thousands of troops and fighters.
Yet, the media portrayed Tet as a win for the NVA and VC. They expounded upon the ability of the NVA/VC to strike in South Vietnam, without reporting our efforts at repulsing them. Cronkite, the supposed "epitome" of American journalism, took 3 minutes to offer a personal view of the war, included in his news broadcast. This was not news, it was personal opinion. Yet, the American public accepted his statement as fact.
This was followed by more and more biased reporting. Instead of reporting that our top military and political leaders were almost inept at running a war (you cannot run a war from a conference room in Washington against a country half-the-world away), the press reported that the NVA/VC was a superior fighting force and was defeating our military time and again.
It wasn't so much Hollywood that turned the American public against the war . . . it was newsdesks in NY and DC.