Even top US politicians, like Albright https://www.jta.org/archive/wealthy-austrian-family-claims-a...

My favorite German proverb is "children are not responsible for the crimes of their parents".

Doesn't work as a response to "this was robbed from my grandfather, you should give it back because benefitting from crime is generally bad".

It absolutely does. You need to end the chain of responsibility somewhere, and stuff that my grandfather did to your grandfather is beyond the line of what's reasonable.

My uncle is a lawyer in Europe who specializes in art law and I can assure you based on listening to him talk about cases, that you are likely to have to return the stolen art if there is sufficient evidence despite any inheritances or intermediate transactions (at least in the nation where he practices).

However, returning the stolen goods is on a different level from taking on the penalties or damages of the initial theft.

So if someone kills you and isolates your family for one generation, that would make it even?

Not only in Germany. Poland got looted by the Nazis and Soviets from both sides.

And that somehow changes the merit of the argument?

Which argument specifically? Your sarcastic overtone make it difficult to detect an actual argument.

Your general remark that Polish art disappeared from Poland is true. Your implication that only Germany was responsible for that is wrong. The german state is generally cooperative, in contrast to the ex-soviet states, in giving back and trying to find solutions. Even from the private side is cooperation - some time ago some private owner gave back art to Poland, which rarely happens.

You did not provide a source for your claim that "German government is kind enough to let Poles bid for the art they carelessly lost".