Why would the citizens of the land of the brave make such effort to denigrate Poles in particular? And the Irish, I think...?
and the Italians, and the Mexicans, the Filipinos, the Russians, the Japanese, the Indians, the ... (you fill in the blank)
because they're different, and we humans are wired to simplify what we see, so if we don't understand something, we ridicule it. It's just most unfortunate, but it takes smart, enterprising individuals to prove the stereotypes wrong, one by one. I'm also happy to say that more educated people tend to be more open-minded, as do people who come from places with a mix of races and nationalities.
It's very far from truth that negative stereotypes don't hurt anyone, and it's just some PC outrage that makes people fight them.
It's also very sad that some people here who tout their education are not only close-minded but proud of it.
Some of these jokes were subsequently brought to Hollywood from war-torn Europe with waves of Anti-Polish bigots
that's actually very funny to suggest that Hollywood is to blame for Polish jokes...
trust me, it's not the Nazis or the Soviets, or any kind of organized propaganda. It's because Polish immigrants used to be unskilled and not adjusted to the culture. I'm saying "used to be." On average. There were exceptions.
It's not a fair picture of an immigrant nowadays to picture them as uneducated and therefore lacking prospects in Poland. Sometimes it's precisely the educated who find better prospects elsewhere. And yes, sometimes it is the uneducated, but again, it's not fair to say that everyone who left Poland is doomed to have a menial job. This has always been the land of opportunity. Very often those who had literally nothing back in Poland, except for a drive and high hopes, here are successful and respected.