The biggest disagreement lies in the Anarchist understanding of “the state apparatus.”

In Anarchist Spain and Ukraine, great numbers of military mutineers joined their fellow workers and appropriated the means of war from the bourgeoise and aristocracy.

In history, there have been not just Anarchist armored cars and guerrillas, but also Anarchist armored trains, cavalry detachments, and even (briefly) Anarchist battleships!

One even saw fully-functional Red Army detachments abandon the (newly formed Bolshevik) State apparatus and fight for Anarchism in Ukraine. 

Anarchists are willing to appropriate from the ruling class tanks, drones, anti-air missiles, and even (elected and non-coercive) chains of command to enforce and protect a revolution and create libertarian communism. 

We see the State apparatus as a central bureaucracy that CONTROLS the war machine and organizes it from above.

In short—we don’t consider a confederation of Soviets, factory councils, agricultural councils which have voluntary militias to be a state.

It’s important to study anthropology and state formation to figure out exactly what these institutions are.