It's just 'might makes right' combined with 'our guy won' and a helping of Western imperialism. You don't need to be a philosopher to see the underlying reasoning.

From what I've heard, you can see about the same thing in Ayn Rand's lectures where she retroactively excused colonization of the Americas because "they didn't do anything valuable with all the land". You know, same Ayn Rand that wrote the bible of US corporatocracy. (Alas, I don't think I have long enough time left to waste on Rand's lectures myself.)