Most missionaries and European colonialists who spread Christianity were themselves not Christian and did not spread Christianity. They were allegiants of the doctrine, but not practitioners of the spiritual principles, a key difference. Hence as they spread the doctrine via the bible, many blacks became similar allegiants of the doctrine (that externally seems like Christianity) but most were not doers of the principles. Most colonialists and missionaries could naturally not spread Christianity because their manipulative, barbaric and inhumane treatment of the blacks contradicted every principle of it. Thus most (not all) could disseminate only doctrine, not exemplify living faith.
During the hardships that ensued through the yoke of oppression, some blacks became Christians. Meaning: the difficulties, hostilities, and subjugation they encountered provided a perfect field and opportunity to apply the principles that, once internalized, becomes a living inheritance of the spirit. Through this assiduity, the said person inwardly undergoes a radical transformation that actually makes them a true Christian in the sense the spirit.
Most white colonialists themselves never went through this process and were thus Christian in name only, the same way many radical Islamists today claim to be Muslim but are just thugs masquerading around as Muslims. Unfortunately, most blacks never truly transformed through this inner process to become a true Christian; instead they became just adherents of the doctrine, in name only, like their colonial masters. Only a few truly transformed above doctrine.
Nelson Mandela and many activists during their time in Robben Island truly transformed themselves. In this transformation, they actually became real Christians and thus showed many of these white apartheid sympathizers, who were merely allegiants of the doctrine, how to be an actual Christian.
They gave him doctrine, he reciprocated living faith. They tried to blind him, but he helped them see. In the end, he and other activists were the actual Christian missionaries to their colonial opressors. The transformed few who eventually “spiritually colonized” them in return with the higher moral principles exemplified through their exceptional conduct.
~Ikenna Q Ezealah