US-Cuban relations

It seems that our policies toward Cuba have been short-sighted almost from the time Castro took power. For decades we encouraged Cuban dissidents to escape and take refuge in the US. One result was the takeover of southern Florida by a large population of angry foreigners with policy agendas of their own and with enough clout to tie the hands of our government in its relations with Cuba. Various embargoes made life difficult for the people of Cuba and prevented US businesses from operating in and trading with Cuba. This exclusion probably prolonged the Communist regime or prevented or delayed its mollification. It advantaged businesses from all not-US countries vis-a-vis US companies. Then there were the unethical attempts to assassinate Castro or overthrow the Cuban government by paramilitary action. The missile crisis came after several of our offenses against the Cuban government. Those missiles were forced (by Nikita Kruschev) on Castro against his wishes. When the Cubans shot down a small US aircraft dropping propaganda leaflets over Cuba, we should have just shut up instead of posturing self-righteously. In any case, normalization of relations with Cuba should have begun at least three decades ago and been completed by now. Why not?