I don’t think you understand the extent of this “embargo”. It goes far beyond simply not trading with them.
It’s not a direct blockade, but the US has in the past threatened to cut off financial aid to any country that trades with Cuba, disallows foreign subsidiaries of US companies to trade, and even threatens sanctions upon foreign companies that do any trade in or with the US that also trade in Cuba. They’ve also begun attempting to strangle their tourism, by disqualifying any person who visits the island from ESTA - which lets citizens from countries like those in the EU visit the US visa-free. This makes travel extremely difficult, requiring a costly and time consuming visa application which could be denied.
The UN has voted to condemn it every year for many years, with usually only the US and Israel voting against. They say it is a violation of international law and the UN charter. (www.un.org/en/ga/62/plenary/cuba/bkg.shtml)
It is abhorrent and unjustifiable, and has a real cost in human lives and suffering.