It’s far more crucial for the left to cultivate the impression that the Kennedy assasination was carried out by “far right” extremists - the CIA, the FBI, Nixon, et. al, then a lone nutcase and self-described marxist who defected to the Soviet Union at the height of the cold war, marries a KGB station chiefs’ daughter and a few weeks later returns to the US no questions asked.
Really it’s pretty impressive when you think about it. Further, the country has really gone down the tubes since that time, since JFK was almost a conservative compared to the ass-clowns that currently hold sway.
Considering what an anti-communist JFK was (he considered Joseph McCarthy a "great American") there is no reason to believe he was going to back out of VietNam. If he were president today, he'd be as villified as GWB. Kinda funny that a guy who admired Castro and Che killed the president, and the people who mourned Kennedy's death had Che posters all over their dorm rooms...