Proven to be causal? Like we'd clone 1000 John Allen Chaus, raise them around the globe, and see how many of them do something fatally arrogant relating to overseas travel?
As an American who has lived on 4 continents, I can confirm that American tourists quite often live up to the stereotype. I have a variety of painful memories of times I've had to intervene and explain things and/or translate for aggressively clueless Americans. Many travelers are great, of course. But I still think the stereotype is justified.
It makes sense, I guess. We grow up in a country big enough that we can travel widely without learning another language or learning much about dealing with different customs. And our wealth and our culture of American exceptionalism make it easy for us to spin the globe, plop a finger down, and expect that we can go there and do as we please. Often it works, even if it does rub the locals the wrong way. And sometimes, as here, it doesn't work at all.