Kennedy repeatedly dismissed other opinions and had to change his positions after being proven wrong. He accused Eisenhower of allowing the Soviets to accumulate more missiles than the USA, and found out he was wrong after getting elected. Kennedy then supported the Bay of Pigs assault, but pulled back at the crucial moment when the rebels needed support, and the whole affair was a disaster. Kennedy even refused to admit that he had agreed to all of Kruschev's terms in relation to de-escalating the Cuban missile crisis, and pretended that it was a victory of American diplomacy and intimidation.
Castro was also a troubled character who actually advocated using nuclear weapons against the USA, and had to be persuaded that it was a bad idea because the fallout would hit Cuba.