Absolutely please do stop doing business with the US.
That being said, making generalizations about the entire population of a country is generally a crappy thing to do (same with any other demographic that isn't just self identification with an ideology defined by hate or cruelty)
America is made of many people, plenty of whom are morons, plenty of whom are not. We unfortunately we have a wildly dysfunctional system of government that morons have gamed to consistently concentrate power in the hands of stupidest and most self destructive.