Vietnam War, a Hollywood hit

There are couple of questions I would like to ask about the Vietnam War and this essay. What is it with filmmakers and this obsession on trying to create a myth about the Vietnam War? I would also like to know why they would do this since I think it doesn't collaborate with their main objective, to make money.

I guess I know a bit about the Vietnam War having read about it in high school. I think the Vietnam War was the third war in which the US was fighting against communism. The first would be the lengthy "Cold War" which was a non physical battle between the Soviet Union and the USA. The second would be the Korean War, where a UN force mainly made of US and South Korean soldiers fought against the North Korean's to stop the spread of communism in Korea. I think the Domino Theory plays a big role in why the US went into Vietnam. Since South Vietnam was supposedly the "domino" that was about to fall to communism after the departure of the french colonials. Since that was the USA's foreign policy at the time, it seemed valid for the US to move into Vietnam as they did in Korea. Also, US forces were being attacked for no reason by the Vietnamese at sea. I also know that we actually lost in the long run as the North Vietnamese run over the South Vietnamese and turn the whole country into a communist state. The US also faced many casualties and spent an excessive amount of money to fund the war. I believe many of the veterans of the Vietnam War didn't receive benefits they should have received and many suffered from posttraumatic stress disorder.