Christianity is not a product of colonialism. About the same time the Gospel spread into Europe, it also moved in the opposite direction into Asia. We just don't have much recorded history on this. It is believed that Thomas was part of the missionary movement into Asia (India). There have been various Christian enclaves throughout Asia (Southeast Asia, China, Korea), like the Miao ethnic group in China.
The interesting part of this is that there have never really existed Christian religious States in Asia. The Christian movements in Asia were generally in opposition to government, whether it's a communist (atheist) State, or a government with an established non-Christian religion. And Christians in Asia generally stay out of politics. Different national and ethnic dynamics.
Europe is a relatively tiny continent that had expansionist visionaries. Peoples who lived in larger continents felt less of a need to expand, at least globally. China would be a good example of a powerful Asian empire that sought expansion, but mostly within the Asian continent. The Native Americans occupied the large continents within the Americas, and there was really no physical need to expand beyond.
So the question is, were the seafarers of Europe motivated to expand beyond their shores by Christianity? Or would they have done so anyway had they remained pagan? If it's the former, then we at least have Christianity to thank for where many of us are now. If the latter, then the idea of Christianity's growth being a product of colonialism is shot.
