"Tankie" is just a pejorative for communist, like "commie" or "pinko." There isn't a subsection of communist thought called "tankie," the fictional "tankie" is a strawman ready-made to be flung at communists to turn valid and reasoned arguments into caricature.
If they were, they wouldn't be tankies... Communists can critic Stalin, tankies cannot.
"Tankie" is just a pejorative for communist, like "commie" or "pinko." There isn't a subsection of communist thought called "tankie," the fictional "tankie" is a strawman ready-made to be flung at communists to turn valid and reasoned arguments into caricature.