Castro rose to power at the point of a gun. I don't recall Castro asking anyone’s permission to seize power.
What you are saying is like saying Russians loved communism because Lenin and Stalin slaughtered tens of millions of Russians to force communist rule for 70 years.
In a revolutionary situation with societal collapse the most ruthless faction usually wins. That’s how Lenin’s Bolsheviks won. Castro’s Communists in Cuba not necessarily societal collapse there but certainly a revolutionary environment. Castro also initially disguised his true ideology and intent and was by far the most ruthless.
Was Castro alone in his revolution? The communist upraising in Cuba was a one man show?