In most of these cases, Christianity did not organically spread. It was brought in and forced upon local populations by mostly western colonial powers. Colonial powers always export their cultural beliefs and identities in an effort to bring those subjugated in line with their own ideas and expectations. Where religion wasn't brought in by colonialism's force, it was exported and introduced by typically western missionaries, yet another example of using a different kind of force to help it take root and spread. After some time, it's true that Christianity began to evolve with its own localized flavor, but it's not like these non-western cultures discovered Christianity via their own Damascus Road experiences with local prophets.

While I can't speak about every culture, in W. Africa, Christianity took root because the colonial powers brought missionaries who established religious schools wherein the practice of traditional religion was impossible. For the longest time, these were the only schools available so the educated became Christian, and thus the powerful and well-connected were all Christian as a result.

An even more interesting comparison is the Eastern Christians of Greece, Russia, the Middle East, etc. Their theology and relationship with science has been fundamentally and increasingly different than the West since the Great Schism.

> While what you say is true to some extent for Western Christianity

Its just as true of Eastern Christianity.

> the fact remains that Christianity has taken deep root in a number of places in the world that were free of western biases, e.g., China, Korea, Africa, and South America.

All of those examples are largely a consequence of imperialism (largely, on the part of societies comprising Western Christendom.)

That's not to say that there aren't a few cases of durable Christian communities in regions (IIRC, particularly in the Middle East and East Africa, and some in South Asia) where they aren't a result of the heritage of ties between the common ancestor of modern Roman Catholic, Protestant, and Orthodox Christianity and the Roman empire, including those descendant churches ties to imperialist European states, these isolated communities are notable as exceptions within Christianity.