I'm not being sarcastic. The effect internet has on society is too big to be understood. How could we, mere humans, actually know if internet has or will have a positive effect on a society? We couldn't, there's no way. Castro, as well, couldn't possibly discern whether internet is good or bad for Cuba, yet it remains that he could have good reasons to prohibit it.
the point being, he has no right to prohibit anything, he took power by force and by populism