I think it is strongly indicative that your underlying bias so colored your reading of the article that you made a very basic factual error. I would encourage you to read it again with a more open mind.
Your bias towards flippantly dismissing colonialism is insulting to those groups of people who experienced it. Do better.
If by any chance that is not what you meant to come off as, you may want to reconsider low-effort passive aggressive one liners as your communication medium.