I’ll often see these same western leftists bring up Cuba as a defense of socialism, which seems to make them stumble less often. Cuba’s a very clear case of socialism defending itself against external hegemony.

It's also a case of how strong American propaganda is, despite the obvious truth just south of them. Sure, most leftists might be at least ambivalent on Cuba, but you will always have the Gusano Defense brigade talking about what an evil dictatorship it is and every political talking head center and right nodding their heads. Even "progressive" Liberals who are against America's blatant imperialism accept the premise that it's a dictatorship.