Why is distribution of resources unfair between rich and poor countries of the world?

The rich countries of the world were, in fact, the former colonial empires, such as: the French Empire, the Spanish Empire, the Portuguese Empire, the Dutch Empire. All these empires owned colonies in South America, Africa, and Asia. Thus, a large part of the resources of the "colonial countries" were transported to the "mother empires", so the colonized countries were left without resources. Precious ores, gold, silver, diamonds from South Africa were transported to "empires", from which we deduce that the financial resources obtained from the sale of precious ores entered the budget of the colonial empires.