Marxist schools have authors. Just as Marxism sprang from the mind of Marx, so we have Leninists, Maoists, Trotksyites, Gramscians, Althusserians... Now consider the different schools of anarchism. There are Anarcho-Syndicalists, Anarcho-Communists, Insurrectionists, Cooperativists, Individualists, Platformists... None are named after some great thinker; instead, they are invariably named either after some kind of practice, or most often, organizational principle.

-- David Graeber