It's Marxists*, Communists are basically Marxists with extra retarded economic measures like no private property, communes, no private kitchen and all, Marxists meanwhile focus more on (((social reform))) and (((progress))).
The American/Western capitalist model is more suited to implementing Marxist philosophy rather than the more direct Soviet/Mao Chinese/Vietnamese model, the process for this started in the 60's with the "sexual revolution" in the West.
Communism has been proven a failure world wide, so the Marxists have reverted to their original form, focusing on subverting the current Capitalist establishments in the West rather than attempting to overthrow them via violent revolution.
Leftist and Liberal ideology has proliferated much more successfully in the capitalist West than in the ex-Soviet Bloc or Communist countries of the world.