My understanding is that Castro is quite anti-religious just like any other communist leader (confirmed by Wikipedia: http://en.wikipedia.org/wiki/Religion_in_Cuba). Hitler was in conflict with Christian churches as well since he was essentially building his own religion and did not want competition. I was born in a country where religion was systematically mocked and religious people had to hide their beliefs. Yet somehow getting rid of the religion did not make people any nicer. I am glad that it is not the case in ex-SU anymore. Tolerance and letting people be whatever they want to be is the way to build a stable society. In the US it may seem like many fanatics are religious, but having seen many examples of the opposite I do not think fanaticism and religion are strongly correlated.