The labour aristocracy in Imperialism is specifically meant to denote leaders of trade unions who sell out the rank-and-file and start doing class collaboration. The term as its typically used online doesn't have much to do with Lenin's definition

Labor aristocracy generally has similarities to Engels analysis of petit bourgeois, but Lenin's usage in the context of imperialism would apply to those with economic status and their role in maintaining imperialism to maintain capitalism rather than the term PMC, associated with cultural "class" and affects.