Starbucks goes to a great effort, and pays twice as much for its coffee as its competitors do, and is very careful to help coffee producers in developing countries grow coffee without pesticides and in ways that preserve forest structure.
We study the injustices of history for the same reason that we study genocide, and for the same reason that psychologists study the minds of murderers and rapists... to understand how those evil things came about.
The southward advance of native African farmers with Central African crops halted in Natal, beyond which Central African crops couldn't grow - with enormous consequences for the recent history of South Africa.