From the perspective of post-colonialism: As a way of justifying colonial occupation, the colonial power can be seen as acting on a fundamental presumption of moral superiority. This is the implicit rationale for the missionary presence in the colonized region (i.e., the colonizers have come to save the souls of the colonized, to morally redeem a corrupt or wrong-minded native population).
This is a basic tenet in the critique of colonialism in post-colonial schools of thought and the idea has ramifications that serve to challenge continuing perspectives on authority (authority to define "the other" and authority to universalize one moral perspective in preference to others).
"Achebe was repelled by the fundamental racism of colonial classics such as Joseph Conrad’s Heart of Darkness and Joyce Cary’s Mister Johnson. These novels depicted a savage Africa that was humanized only through European colonialism" (eNotes).
How does Achebe articulate the "foundational misogyny" expressed in the moral presupposition that one group has moral authority over another in Things Fall Apart? The novel presents a colonial occupation of the Ibo villages that is accompanied and justified by a missionary presence whose aim is to convert (and thus "to save") the native population via Christianity.
The English occupying group presumes that it possess an inherent superiority, that its moral code is truly good and that of the natives is less good or not good at all.
The moral traditions of the Ibo dictate the lives of the tribes, defining sacred and profane spaces, outlining taboo behavior and places, and functioning as a means of social coherence. To themselves, the Ibo are completely intelligible in terms of their moral systems, even if those systems create situations wherein a person like Okonkwo can go unpunished for killing one child intentionally and later be punished for the accidental killing of another.
The fact that the Ibo and the English are governed by two distinctly different moral codes is expressed in numerous episodes in the novel. One moment in particular speaks to this idea very directly. While Okonkwo's body still hangs from a tree, his tribesman send for others to come and take him down.
“Why can’t you take him down yourselves?” he asked.
“It is against our custom,” said one of the men. “It is an abomination for a man to take his own life. It is an offense against the Earth, and a man who commits it will not be buried by his clansmen. His body is evil, and only strangers may touch it. That is why we ask your people to bring him down, because you are strangers.”
To the colonizers, the Ibo customs are not understandable. To the colonizers, the Ibo need to be saved. This is the presumption and the locus of the foundational misogyny because this idea essentially excuses the occupation and exploitation of the natives. Creating an implicit economy where the missionary colonizer has performed a service for the natives so that the natives then owe allegiance or subservience or some other payment to the colonizer as compensation for salvation, the presumption of moral superiority links directly to an assumed authority (morally, economically and politically).
Achebe's novel successfully illuminates the differences between the moral perspectives of each group and, by examining the damage done to the integrity of the native society, also demonstrates a basic misogyny within the very conception of missionary colonialism.