Castro actually received a ticker-tape parade in NYC. He was promoted by the press as a hero and Batista was portrayed as a beast. Batista was a moderate socialist himself, but had actually been fairly good for Cuba, which was prosperous and moving ahead (it had the third highest literacy rate in the hemisphere, for example). But Castro was the press’ 1968 dreamboat: he was a young university student revolutionary from an upper class family, good looking in his fatigues, cute when photographed holding a gun, and he made them swoon.
It was only later that it became so obvious that he was a vicious Marxist with a bloodlust and visions of personal power that even the press couldn’t cover for him anymore.
You are right about Batista, but wrong about Castro. He was not from an upper class family, he was from a rich family; there is a big difference, especially in Cuba. His viciousness was already well-known, his revilutionary gang had mounted an assault on an army barracks in 1953, assaulting the sick and wounded soldiers in the barracks’ hospital. Furthermore, the US ambassador to Cuba, Earl E.T. Smith, had already traveled to Washington to warn and advise Eisenhower that Castro was a red, and Eisenhower’s response was to remove Smith from his post and replace him with another ambassador. Castro’s favorable reception here was orchestrated by the NY Times and ultra left members of the State Dept who knew who and what Castro was. This is all in the public record, in multiple sources.