It might have been wrong for them to agree to the rockets on their island, but that was all after the bay of pigs incident.
Maybe, if the US and the US mob would not have been so friendly to the dictator Batista, all of the revolution etc. would not have been needed.
It was a democratic society (from what I remember, learned and just read) until the democratic government was ousted out of power by a military coup, an illegal government which was quickly recognized by the US as the legitimate government of Cuba.
You can point towards the guilt of Castro but Castro could point to the guilt of the US government, US companies and US mob for the power of the dictator Batista. This all started with Batista, not with Castro.
Maybe the situation would have been a lot better if the US would not have gotten involved with Batista but would have supported the legitimate leaders of Cuba. The US supported Batista with aid that virtually all came in the form of weapons to strengthen the Batista dictatorship.
Further the US government used it's influence to increase the profits of US firms and made it possible for just about every natural resource of Cuba to come into the hands of American companies. At the urging of the US government ITT was allowed to raise the telephone rate in such an excessive rate that out of thanks ITT gave the US backed Batista a solid gold telephone.
Sorry, but Castro was a response to the crimes of Batista and the government that supported him.