Well, yes, the plan in its final form was indeed ludicrous.

The plan emerged from the CIA with Allen Dulles and Richard Bissell. The CIA planned this invasion during the Eisenhower presidency. The CIA recruited exiled Cubans in Miami and trained them in Panama.

The original plan was for the exiles to land in Cuba and receive support from Cubans who disliked the Castro regime. If the exiles came into contact with superior numbers, it was originally expected that the US military would provide support. John F Kennedy did not want the military so obviously involved with the operation, so he ruled out anything more than dropping supplies. JFK did not want the world to know that the US took such a large role with the overthrowing of Castro. This is a break from the Eisenhower administration who in the past has openly supported the CIA operations with the military. Hind sight being 20/20, there was nothing that could be done to hide to obvious facts that the US was involved in the Bay of Pigs invasion.

When Dulles and Bissell briefed the newly elected president on the plans of invasion they said the chances of success were high. When Kennedy said that there would be no military support for the exiles, those chances never diminished. Dulles and Bissell were still operating under the thought that Kennedy would use the military to aid the exiles much like Eisenhower aided other CIA operations with the use of force.

The Americans never new how well armed the Castro regime was. During the invasion, the exiles were given 4 B-26 bombers. But, these were shot down. The Soviets supplied the Castro regime with weapons. When Kennedy was told that the Exiles were stuck on the beach, unable to reach the mountains in order to start a guerrilla war as originally planned, Kennedy still refused to let the military get involved. Kennedy was still try to hide the fact that these exiles were supported by the US (Why? no one know how he was going to try to hide the B-26 bomber).

Kennedy felt he was lied to and pushed into this disaster. Before the Bay of Pigs invasion there were already news reports and rumors that the US was training exiles in Panama to remove Castro. And what would happen if Kennedy decided to not go through with the invasion? Kennedy thought that he would look weak on Communism, hundreds of Cuban exiles would be talking about how they were willing to fight Castro but, Kennedy didn't want them too.

I can give sources when I get home from work.

Edit:

Kennedy's Wars: Berlin, Cuba Laos and Vietnam by Lawrence Freedman

President Kennedy: Profiles of Power by Richard Reeves