@90sRetroFan
The liberals say that the colonialism happened not because democracy. And it happened because of authoritarianism. And they also answer with the other arguments that colonialism was not presented "the real democracy". So, what about that arguments?
My current answer is even colonialism still happening during the period of liberalism and democracy in the colonist nations. And only the second world war which made it end, even more quickly, not the democracy. But any other strong arguments?