I'd say it is rather important to know where you are coming from. The people colonizing the USA did not appear out of thin air, but out of a complex group of nations with a wealth of backgrounds, which is completely lost if you don't learn enough about the world at large. And this is not about eurocentrism at all, since there are a lot of people out of African and Asian nations too.

I also think it is not surprising that the average American doesn't know shit about the complicated development of the human race, which comes with a shocking ignorance towards ideas like humanism and why the founding fathers were so adamant about the separation of church and state, which is increasingly becoming lost in the USA (hint: it's because the founding fathers knew about all this stuff!).

If you compress 10,000 years into a third of 250 years, this is what you get.