The US Marine Corps and the US Navy were not overly opposed to the war, operating in that region was no stranger to them. However with the United States Army and Air Force, they were EXTREMELY upset about the war. Asia is not the traditional fighting place for the US Army or US Air Force. Secondly, congress approved defense budgets for the construction of fast super-sonic jets and expensive battle tanks for the US Army...specifically for war in Europe (the old "Fulda Gap" war plan). Every Army and Air Force officer spent his whole career planning to fight the Soviets over the Fulda Gap (the planned and traditional invading place from the "bad guys"), and the rest of Europe. Half of the US Army was stationed in Germany (even Elvis Presley served there...as a Patton tank crewman!). The US Army and the US Air Force wanted to fight in Europe; that's where the money was being justified to be spent; that's where the high priced war equipment (tanks and aircraft) were being designed and built for war...EUROPE! By an ironic twist of fate: Every bit of those "Built for European War" machines, NEVER did get to fight in Europe. But they did fight in Asia TWICE! (Korean War & Vietnam War).
Many Americans were against participation in the Vietnam war because administration after administration failed to explain to the American people what exactly were the goals of an American intervention there. This led to the emergence of the "Credibility Gap" in American politics. People felt that the government was lying to them about deaths in the war, costs associated with the intervention, and the ability of the American military to prevail there.
Even George Kennan, the architect of Containment Doctrine (we must stop the Soviet Union from expanding), was against the war in Vietnam because he did not see a strategically vital interest for America there.
Others were against the war in Vietnam because of the horrific casualties for the local people. Hundreds of thousands, possibly even millions if you count the surrounding countries as a part of the overall conflict, died as a result of the American intervention. Many believed that America should not be bombing civilians in a third world country, however vital the strategic interest.
And of course there were those that did not want the American military put into harms way unnecessarily. Because of the draft, many, many more people were affected by this war than wars today, so many more people felt the need to protest the war. The prospect of being drafted and sent off to die in a foreign jungle was more real to those protesting than those who protest the Afghanistan war today, and much more widespread.
Others were against fighting in the Vietnam war because they believed blacks and less affluent members of society were disproportionately drafted due to the lack of knowledge on how to get around the draft. These protests actually later spurred the Civil Rights Movement to protest and galvanize support until it was transformed into the powerful cultural force it eventually became.
Their sons were getting drafted!
Americans were drafted into the Vietnam War in 1965.
Hawks which were the people who were for war including the Vietnam war.
Many famous people opposed the Vietnam War, including Gene McCarthy, John Lennon, Bob Dylan, Jane Fonda (who went a bit too far), Gore Vidal, and many more.
Because rich people choose not to go while poor people didnt have no choice but to go and because they didnt approve fighting with anyone
Try: Statistics About The Vietnam War. Recommended by the History Channel.
Some people were against the Vietnam War because young men were being drafted to fight in the war.
Doves are those who desire peace over war. Hawks support war when necessary to resolve a conflict or subdue an enemy. Consequently, it was the doves who opposed the Vietnam War.
Students for a Democratic Society
Many people still don't know because he was assassinated but many assume he would have expanded the war effort.
See: List of anti-war organizations.
Those that didn't have to fight it.
Matthew Farmhouse and Co.
College students. (They were draft age).