I believe western cultures were arrogant. While they had "well meaning" justifications for spreading their culture, the root of it was arrogance. Each western country was in a competition to colonize the most land. The more colonies you had, the more powerful you were. Colonies gave them raw materials, which they desperately wanted for their economies. In fact, when western countries colonized, the colony's old economy typically collapsed, such as when Great Britain colonized India. Yes, they used Social Darwinism and "survival of the fittest" as justifications, tricking the colonies into believing it would help them, however, the true benefits were for the imperialist.
