I perceive that part of the reason the west doesn't wade into the conflict in Ukraine (rightly or wrongly) is that there is a fear of the conflict escalating into a brawl between western nations and Russia (which is probably at least a near-peer to western militaries and nuclear armed). Venezuela is neither a near-peer military power nor nuclear armed as far as I understand, and their ability to hit back (again rightly or wrongly) against other regional powers, the US or whatever other western nations that might intervene (maybe Britain or France?) seems very limited, and thus Maduro's tactical and strategic position seems really different than Putin's.