Someone who hates everything not created in the US and feels the need to harass people who do like things from different countries and cultures.
It generally could get worse or better
you stated the median level ameriboo
passive ameriboos generally don't like eastern, mainly japanese video games). anything other than that is perfectly fine. but they still hate when others play them and harass them
General Ameriboos: you stated that above. only anything basically made in the US/Canada. Anything with non-western influences. Yes some don't even like things like DmC or Dark souls because it isn't western made
Hardened Ameriboos: Also note the term "bro gamer" is associated with them. They are the worst. Basically if it is not a sports game(includes racing) or an FPS like CoD they don't like it when they don't even try it. There aren't many compared to the others. They will even lol at you for playing things like Asassin's Creed or Skyrim.
"CoD man! GotY for sure dude! Best ever" ~one of many used by them every year when a CoD is released.
You will know when you find one of the hardened ones. The term Ameriboo is not always pertained at just americans though
Of course they reserve their right for an opinion but it is their harassment of those who like Japanese/eastern games that gets them this title