Marx disagreed both with Proudhon and Bakunin precisely on the question of federalism (not to mention the dictatorship of the proletariat). Federalism as a principle follows logically from the petty-bourgeois views of anarchism. Marx was a centralist. There is no departure whatever from centralism in his observations just quoted. Only those who are imbued with the philistine "superstitious belief" in the state can mistake the destruction of the bourgeois state machine for the destruction of centralism!
Now if the proletariat and the poor peasants take state power into their own hands, organize themselves quite freely in communes, and unite the action of all the communes in striking at capital, in crushing the resistance of the capitalists, and in transferring the privately-owned railways, factories, land and so on to the entire nation, to the whole of society, won't that be centralism? Won't that be the most consistent democratic centralism and, moreover, proletarian centralism?