A mistake that led to the enslavement of other people on behalf of the capitalists, then led to the colonial countries turning into 3rd world attractions, again on behalf of the capitalists.

Also there are other aspects rarely talked about, like the use of coloured troops against European populations on European soil like the Marocchinate (not only by Brits and French but also by Germans), or the fact that the Ottoman empire was also a colonial force and the European colonial forces rejected the concept of nations under Ottoman rule gaining their freedom for obvious reasons. Not to mention that colonial competition between Italy, Britain and mostly Germany led to the sacrifice of the White and Christian populations of Asia Minor and the subsequent mess in Middle East (Iraq, Lebanon and so on).