But what's this about?...
nott: they put ketchup on everything
a British stereotype of Poles :) We put ketchup on everything. And it's based on sound foundations. Ketchup helps you to actually eat English food. Lots of ketchup. Helps a lot.
There's one exception, though, fish and chips. They got good fish here.
nott: Orchestrated Anti-Polish campaign
i think i would ask for more proof than the fact that the Irish like to drink...
I think you would. Only it's me who's asking. Not that I am trying to be difficult, I just can't see a natural reason, so I'm assuming a reasonable explanation. Like, was there a channel, or a program, specialising in Italian jokes?
This reasonable explanation of mine is not the answer still. Still we do not know the reason for this campaign, do we? Although some ideas may lurk around.
America might have dumb Polack stereotypes, we have dumb Paddy stereotypes, France has dumb Arab stereotypes, Germany has dumb Turk stereotypes, Poland has dumb America/Russia stereotypes,
Thick Paddy in England has historical roots. Rather strong interaction and the need to denigrate the wronged nation. French and German stereotypes about Arabs and Turks (if it's true) come from the massive and troublesome recent migration. Polish jokes on dumb Russians are just a part of 'Russian jokes', and have easy to spot historical reasons too. America is a big, easy target for everybody, still the majority of jokes about Americans are not about their stupidity.
Poland and Poles, for Americans, were either non-existent or unimportant, few of them knew what this ethnicity was about. America never hand any contact with Poland, and Polish migration was incomparable with the recent Muslim deluge. Poles integrated just like any other nation. Poles didn't show any striking vice, like Italians, or the Irish - so they were hit by the ever handy 'stupid X' stereotype. The question is, why.
Unless you really can prove what you claim - that, unlike other countries, Poland exported a mass of idiots. Or that idiocy is national Polish characteristics, so there was nothing else to export.