The point was that books that were written by people who were the enforcers of imperialism would have a certain bias. Would you celebrate Columbus Day if you were living in the US? Or, would you believe the American version about the Vietnam War? Would you uphold the bible, with its sexist implication of women? Would you just take the Israeli version of the Israeli Palestinian conflict and believe that Jews are still-hunted down and that everything is justified by that cause? History as know it were wrote by the imperyalist and the dominent.
I recommend you too "the people history of the us" by howard zinn.
And there is a different between a war that is wages to liberate humanity and a war that is fought for imperialist reasons. The ruling class would never just step down and allow the oppressed classes to just rise up. Capitalism arrives from feudalism not without war and blood shed. From the American and French revolution to the Russian and Chinese revolutions old classes never just step down. Without a revolution the oppressed have no chance.
I'm happy to see that you agreed with everything else I said.