Because cubans are considered a poor, third world country (despite the definition being something different) and because USA considered them an example of evil communism. Sure, communism then was far from ideal, but at least now they have healthcare (according to OP)
Booby trapping violate the same traties, especially hiding explosives in food. If ukrained wanted to commit war crimes, they would choose the smart way, this is just idiotic russians feeding lies to idiotic people