Here is how I understood your question:
"Justify" means "to prove or show to be just, right, or reasonable" (Mirriam-Webster online dictionary). It seemed like you were asking if the West is trying to use democracy to go back and say that it was perfectly reasonable to colonize.
So, I said that I don't think the West is trying to say that they were right in colonization. Rather, they (we) realize that it was not a good thing, and think that spreading the option of democracy is better for the people.
I'm not really sure why you didn't think I understood your question. Did you mean something different than "justify"?