I do not think it is relevant today, but during the Cold War their crime was being all buddy-buddy with the USSR and offering to host some of their nuclear ICBM

I do not think it is relevant today, but during the Cold War their crime was being all buddy-buddy with the USSR and offering to host some of their nuclear ICBMs. The USSR is long dead though, and nobody is asking Cuba to hold on to WMDs for safe keeping, so the continued sanctions make no real sense in 2022.