Here's the deal. You don't refer to other people as Hitler or Stalin because it's cliche (same with Winston Churchill, which of course is an indirect reference to Hitler). That does slip out of people's mouths occasionally, and it's annoying. However, to refer to yourself as like Stalin, and talk about how he defeated Hitler, takes you to an entirely new level of rhetoric. That is where Nicolás Maduro went, even calling him "comrade."
“Por aquí tienen, Stalin: Historia y crítica de una leyenda negra. Mira, Stalin se parecía a mí, mira el bigote es igualito. El camarada Stalin, que venció a Hitler”, afirmó.
The book he's referring to is a revisionist history of Stalin, intended to salvage his negative reputation. Make of that what you will.
It's common to blame the mainstream media (or bloggers for that matter) for mocking Maduro, but he says a lot of weird stuff.