"In the course of its revolutionary struggle, anarchism not merely overthrows governments and discards their laws, but also sets about the society that spawned their values, their "mores" and their "morality", which is what makes it increasingly comprehensible and digestible to the oppressed portion of mankind." (N. Makhno, Our Organization)
This statement sets itself up to be easily knocked down by the classic argument against anarchy.
To create a sustainable anarchic society (well, collection of people at least... I don't know if the word "society" could be used in the absence of societal structures), it must be assumed that all people in the society would act positively, or at least non-negatively, toward their fellow members of that society. Hence, a collective morality of sorts which looks a lot like theoretical libertarianism would develop, with the minimal societal rules/laws that libertarians do support replaced by this collective ethos. Negative/destructive acts by a member or members of the society towards another member or members would cause the downfall of the society, as human desire for vengeance would lead into a destructive cycle.
Makhno seems to advocate the rejection of societal morality in this statement. Without a societal morality, human instinct takes over, and human beings are not naturally good.* For an anarchic society to work, the whole society must first believe in the same moral framework, then adhere to it (which is even harder than achieving the collective belief). Reject morality in and of itself, and your anarchic society has tossed out the one necessity for it to possibly work.
* Yes, I know that's my Protestant belief showing through. The whole WU is opinion. Deal.