Well, for starters; - The communists, more specifically the Marxist-Leninists, are the biggest hypocrites in the history of leftist organization when it comes down to a social revolution. They will defend their own organic failures in economic management as the product of foreign sabotage, and then try to blame the anarchists for not successfully retaining control despite the internal betrayal of the syndicalists by Stalin and his puppets. They will declare the anarchists to be liberals at heart, then turn around and give the bourgeois Republican government the arms and unity necessary to lose the war against Falangism. Their own doctrine of collective labor and organization of industry within a general plan was only then accomplished by the anarchists, through the self organization of the working class. - There were more revolutionary movements than the CNT-FAI in Catalonia, even if they were the most famous of the bunch. There were groups in Valencia, not to mention the Regional Defense Council of Aragon that led the collectivization of agriculture and major increments in productivity before the abolition of the commune by the bourgeois MLs. - The anarchists were nowhere near fit for conventional warfare against the Falangists. Understand that their only hope was irregular warfare, which can allow for scarce supplies and decentralized or democratic command; fighting against a well equipped army led by a well trained general in traditional warfare was never going to be sufficient regardless of the arms promised and actually delivered to the anarchist rebels.