That's silly. We built and improved upon the culture and certainly don't take responsibility for the Holocaust or Facism or Communism. The US was settled by many more people than just those from England, Spain, and Germany. We have the most diverse population in the world, including from Poland, e.g., Kosciuszko and Pulaski who were instrumental in getting our independence from England.
Americans are not exceptional as they share the sinful nature of the rest of mankind.
Elements of USA culture were formed by Puritans who committed the first planned and possibly the only legal genocide on Irish Catholics. Native population of America was to large extent eradicated. Chattel style slavery was abolished the latest in Western world.
You cannot compare three thousand years of European history with two hundred years of USA. And USA is old as Europe - as de facto it is a part of Europe, you cannot understand America without her European past, America was not born fully formed like Athena from the head of Zeus.