That's part of what it means to be a melting pot culture. The Big Leplowski isn't insulting or deriding some individual or family out of malice - it's a celebration of an important cultural production.
I have an “Eastern European” last name too but I’m not Eastern European. My family has been in the US for at least three generations and come from all over Europe and different ethnic groups therein. I can’t call myself anything but American, and my last name is now American too.
The entire world makes jokes about USA and a lot of them treats it as their duty to comment and laugh about various aspects of USA. This is human, and it is what makes global society great. You just want to screech about something. You couldn't even use a real account for it. You knew you aren't being a good sport.
