I don't think our ancestors were any more evil than many of those they were trying to subjugate. Sure, there were brutal people in power and punishments were severe and, to our more squeamish minds, were sometimes quite stomach churning.
I hear people calling the Saudis barbaric in their use of beheading as a means of execution. Is this any more brutal than passing high voltage electricity through someone or injecting a cocktail of drugs? In fact, it's probably a quicker death.
American treatment of the native indians was often barbaric and ruthless. Brutality is still used as a means of population control in some parts of the world today.
So, the answer is a resounding NO