Lenin used the term “progressive “ because it came across as more palatable a word than “Marxism” or “Communism” in the Communists’ campaigns of massive brainwashing in the quest for world domination.
For example:
“We fully regard civil wars, i.e., wars waged by the oppressed class against the oppressing class, slaves against slave-owners, serfs against land-owners, and wage-workers against the bourgeoisie, as legitimate, progressive and necessary.”
Lenin, Socialism and War (1915)