Y'know, I was buying Poland's argument, until I saw yours. You're exactly right. The time to settle up is right after the war, and events that occur some sixty years later should have had the reparations figured into them.
Poland's present day economic situation comes from its time spent under communism, perhaps there should be reparations paid by Russia to the former Warsaw Pact nations. Now that's within recent history.
The Poles would have loved to have settled up after the war. Unfortunately, the Soviet Union wouldn't let them.