I actually considered listing them as additional examples, but I had to stop somewhere and they had their own distinct wrinkles.

I think the major difference in their respective cases pertain to the ideological dynamics of the particular strains of communism that manifested in those countries. What they lack is a fixation on the purity of national heritage as a primary source of moral truth and a foundation for a self conception. Instead they tended to regard themselves as part of universal, international struggle and understood conflict in economic and ideological terms. What they had in common was the sense that conflict with this chosen enemy necessitated authoritarianism.

There's more than one path to authoritarianism, and they overlap. Different mechanisms don't disprove one another, they exist side by side.