Ike was not a Conservative. Given the mess he left and the disastrous wipe-out of the Republicans in 1958 on his watch, he could not have inflicted nearly as much damage had Truman persuaded him to run as a Democrat.
Our government was infested by the 1950s with Communist/leftist agents and sympathizers. As Humberto Fontova pointed out, about the only person who was anti-Castro was the then-Ambassador, Earl Smith. Batista, of course, was no prize, but compared to what followed...
As I said, I have little regard for JFK. He stole the 1960 election and put the whole nation on the wrong course. Nixon actually won, and he would not have kow-towed to the Soviets. He knew Khrushchev was a blustering phony and could handle him. He would have taken out Castro early on (by 1969, it was too late). JFK was so far out of his element that he was as bad as, if not worse than, Emperor Zero. He had most of the media covering for his escapades and incompetence (and they still do today). He was a sex degenerate and addicted to narcotics, both of which gravely jeopardized his ability to serve.
At this point, what difference does it make. Nixon was no conservative, either. On the contrary, he was an admitted Keynesian, with the likes of John Ehrlichman running his domestic policy and implementing affirmative action in government hiring. He was only concerned with foreign policy, and his accomplishments included losing the war in Vietnam, and detente with Russia and China.
None of the ruling class in the 1960s and ‘50s were paragons of conservative virtue. I am not interested in branding the Kennedeys as such, either. The lot of them were ciphers at best, and I’m identifying them as such. It’s actually reassuring that Teddy was a knee-jerk liberal, in addition to being a murderer, a fat drunken pig, a traitor and a lecher.
Conservatism as we understand it today began politically with the Reagan presidency, and intellectually with Wm. F. Buckley Jr. launching Firing Line and the National Review, or earlier with Milton Friedman.
At least JFK and Robert Kennedy supported McCarthy when even Eisenhower didn’t. And make no mistake, if he were as much of a snake regarding JFK as you claim he was, he wouldn’t have even needed to fake sick to bring about his downfall, either. He could make it to the event, and then thoroughly humiliate him in front of everyone, sort of like what the daughter of a man framed for murdering his wife did in that Maureen show while offering to help clear his name (and only failed to get him convicted for the crime she in fact committed against her mom because the opposing attourney made the mistake of trying to blackmail one of the maids with deportation into giving a completely different story). Even taking some sadistic joy in humiliating him. I’ve seen that kind of thing happen.
And JFK at least was still pro-American and anti-Communist (certainly anti-Communist enough to actually ally with McCarthy), unlike Emperor Zero who didn’t even try to hide his rabid anti-Americanism.
Besides, George Lucas, a huge leftist and likely a Marxist based on past comments made by him in the 1980s when gloating about the Hollywood System’s downfall, outright hated JFK based on what he said in that interview with TIME about Attack of the Clones, where he implicitly compared the Kennedy family to Nixon when explaining why the Empire was formed: https://web.archive.org/web/20020423000824/http://www.time.com/time/sampler/article/0,8599,232440,00.html
Specifically: “I’m more on the liberal side of things,” [George Lucas] says. “I grew up in San Francisco in the ‘60s, and my positions are sort of shaped by that ... If you look back 30 years ago, there were certain issues with the Kennedys, with Richard Nixon, that focused my interest.” Lucas’ own geopolitics can sound pretty bleak: “All democracies turn into dictatorships—but not by coup. The people give their democracy to a dictator, whether it’s Julius Caesar or Napoleon or Adolf Hitler. Ultimately, the general population goes along with the idea ... What kinds of things push people and institutions into this direction?”