What clashes in values are created by the functioning of the British courts? (chapter 20 ...and not the final phrase of Obierika's last speech, which alludes to the title of the novel)

Okonkwo had hoped to return to his fatherland with joy and celebration, but he finds Umuofia sadly changed. The Igbo are no longer free to dispense justice. For the crime of manslaughter, Igbo custom demands the relatively humane punishment of exile. The white man, in contrast, demands execution. White laws are not superior or more humane than the laws of Umuofia, yet the whites insist that Igbo laws are inferior. In building their courthouse, they rob Umuofia of its self-determination.

The religion and the new government are wreaking havoc on the harmony of Igbo life. Social instability and the threat of violence have arrived in full force, and armed resistance is impossible. The old religion is threatened; with humiliation, the Igbo are forced to bow down to white authority.