A key feature of liberal democracy over the pre-existing aristocratic oligarchies was providing a classless society (which, superficially, as classes were defined under aristocratic systems, it does.)

The entire analysis of capitalism which articulated the class system with which it replaced that of the pre-existing aristocracy and revealed the elimination of class to actually just be a switch in its structure and elevation of a new ruling class was by Communists.

Liberalism means no state-enforced classes but doesn't promise forcing everyone into the same class. Commies promise the latter, but in fact enforce a class structure of their own.