I don't agree with any of this, and I've had to write very extensively about JFK and the Vietnam War. Put very simply Kennedy kept advisers in Vietnam as a concession to the hawks in his party because he had given too much ground everywhere else and he wanted those advisers gone after the 1964 election. Kennedy had appeared weak at too many other times such as not invading Cuba during the Bay of Pigs, withdrawing missiles from Turkey, the Berlin Wall coming up, and a bad appearance with Khrushchev at Vienna. He couldn't cede more ground to charges that he was weak, but he had made plans to withdraw those advisers after the election. James K. Galbraith later confirmed this plan existed (
http://bostonreview.net/us/galbraith-exit-strategy-vietnam), and Johnson's National Security Adviser Francis Bator later confirmed this plan remained in place at Kennedy's death. In recordings Johnson and McNamara spoke at length as though they are reversing Kennedy's decision to withdraw from Vietnam.
Kennedy loved the CIA in the sense that he had a fascination with espionage (he had read all the Bond novels) but this made him more skeptical of CIA claims, not less. He was aware of how deceptive that organization could be to achieve their agenda and had been burned badly by the Bay of Pigs. Kennedy also had a well known skepticism of the military that began in his WWII service days. During the Cuban Missile Crisis he believed in his own judgment and not what the military and the CIA was telling him. If Kennedy had anything it was the willpower to go against the intelligentsia of the day and follow his own judgment, as the Bay of Pigs and the Cuban Missile Crisis showed.
What escalated Vietnam to a full-blown war with 500,000 troops was the Gulf of Tonkin incident and Johnson. That man was unbelievably uncurious about foreign affairs and bought everything the military or CIA told him. Many members of Congress were so stunned that Johnson escalated the war (in their eyes, unexpectedly) to the degree that he did that they passed the War Powers Act of 1973 in response.
Can you elaborate on this? Kennedy and his team were about the only people in the room not calling for very hardline tactics like bombing Cuba that would have resulted in World War 3.