Cuba has long had good relations with Russia. It was a key ally to the former Soviet Union during the Cold War that briefly hosted nuclear missiles at Moscow’s behest during the 1962 Cuban Missile Crisis.
Again on October 19, 1960, almost two years after the Cuban Revolution had led to the deposition of the Batista regime, the U.S. placed an embargo on exports to Cuba except for food and medicine after Cuba nationalized the US-owned Cuban oil refineries without compensation. On February 7, 1962, the embargo was extended to include almost all exports.
I would argue the original reasoning was very valid. Helps to know the history though, I guess.