I can't help but notice Americans celebrate their European ancestors despite them fleeing persecution by their fellow countrymen, or Australians happy to accept their heritage despite many of their ancestors being exiled there in penal servitude by their countrymen.
Americans don't tend to celebrate that specifically as much as people celebrate shit like "Oh I'm 30% Italian so I know what a good pasta is!" and things like that. People tend to only see the bright side of their heritage and not the bad shit. Because quite frankly if you go back far enough, everyone's heritage is a shitpile. There hasn't never been a human culture in the history of our race that wasn't a bunch of murderous bastards with dreams of domination. Human history fucking sucks dude because we are a shit species all things considered.
However an argument can be made that the violent history was a product of it's time, in which people needed to hunt for the best lands for survival, and by controlling more land meant more survival. Everything can be attributed to a product of it's time, culture's included. Think about the oversensitive nature of Western culture now, when a rape joke is considered the worst possible thing on the plant. 40 years ago that was just Richard Pryer being one of the best comedians on the planet.
I think our oversensitivity stems from our genuine lack of real problems in the Western world. You know why you don't see Feminism in Islamic dominated nations? Because they would be executed.
Our history of violence and domination has made humans what we are today. With innovation and education we've civilizied ourselves, but that never stopped our urge to fight. Which is why we fight for basically nothing these days. We fight to try and shutdown a comedian we don't like. We fight to silence people who's political views and opinions are different than our own. Because we are violent by nature and must fight. One way or the other.
And that need to fight will always be there, regardless of how we mature as a species. We will fight anything.
You know why people always come together during natural disasters? Because we find joy in fighting against mother nature. After a disaster everyone affected is suddenly in a fight, against that big ***** of a planet trying to fuck with us. So we ban together to help each other because that's the only way we can fight back against disaster like that. When terrorists blow up a couple of buildings, suddenly the whole country is cool because it turned everyone's fight against the fuckers who did that.
We're animals and that's what we do.