No, it makes my point. To what international governmental body did Cuba (or Iran, or Venezuela) file a complaint to say it was illegal?
Other countries joined in or did not.
Cuba would really have no basis to complain to any international body if the U.S. imposed an embargo against Cuba for U.S. trade. One country can't force another one to conduct business.
They would, however, have grounds to complain if the U.S. tried to enforce such an embargo on trade between Cuba and other countries.