Have you met Americans? And the myth of "conquering the West"? Heck, we just had a president who thought Andrew Jackson was the best thing since sliced bread -

Have you met Americans? And the myth of "conquering the West"? Heck, we just had a president who thought Andrew Jackson was the best thing since sliced bread - and that guy is sort of the textbook definition of a cheerleader for genocide and slavery. So, yes, people rationalize a whole lot of truly horrible stuff if it was "their" group doing the horrible stuff. Edit: To be clear, that's not specifically about Americans or Portuguese. The "when we did it, it was good, but otherwise it's horrible" thing is a pretty universal trait.