"The Zaolzie region was created in 1920, when Cieszyn Silesia was divided between Czechoslovakia and Poland. Zaolzie forms the eastern part of the Czech portion of Cieszyn Silesia. The division did not satisfy any side, and persisting conflict over the region led to its annexation by Poland in October 1938, following the Munich Agreement. After German invasion of Poland in 1939, the area became a part of Nazi Germany until 1945. After the war, the 1920 borders were restored."
To my knowledge there's no evidence that Germany and Poland colluded in the annexation of Czechoslovakia but Poland definitely did take the opportunity to annex part of it. And the Germans weren't particularly unhappy about that as it played very well for them internationally.
* History of Poland
This is the direction recent act about "Polish death camps" is heading in. It will outlaw saying Poles were originators of any WW2 war crimes. This is ridiculous. Yes, several million of Poles were killed in WW2. But there are black sheep in any society, and certainly there are in an oppressed one. When you harm a group of people, some of them will invariably hit back. How often do you hear that widely admired Józef Piłsudski was a terrorist and a train robber in his early years ? That Polish resistance conducted assassinations and bombings, not just on soldiers but also on civilians they determined to be collaborators ? Kazimierz Wielki (Casimir the Great), praised for development of Poland under his rule, was a cynical womanizer.
Even a single person can be both good and bad. By whitewashing Polish history, Poland shoots itself in the foot. You shouldn't expect to get correct output if you provide incomplete input. Poland has aspirations to be a regional power and to form an alliance of countries under its leadership. It's not going to happen as long as Poles refuse to remember their wrongdoings towards other nations and groups. Poles will just continue to wonder why most neighboring nations don't like them. You need to remember your mistakes to avoid them in the future and/or to apologize for them, if only in a symbolic manner. Look at what Germany is doing. Yes, Germans supported terrible genocide under Hitler, but they're now doing a lot to prevent that from happening in the future. And Germany is doing really well as far as diplomacy goes.
The eye-opening moment for me was when I was preparing for final exams. We had extra history lessons, and our teacher would force us to think. She would tell us what happened, and asked us why did king X or pope Y do that. Or she would divide us into two groups, like Spartans and Athenians, give us source text and ask to prepare a speech arguing our city-state is better (contemporary Greeks considered Sparta to be a realized utopia).
As for the word like "szmalcownik", throw it around enough times and it will lose its power. For example, in Ukraine both sides of conflict call each other "fascist". In Poland, both sides of political conflict call each other "communists" - but very few actually back up their claims.
My favourite: "targowica", used by right-wingers to accuse political adversaries of treason. However, members of Targowica Confederation:
* had a conservative point of view,
* were hostile to western Europe,
* criticized contemporary Polish constitution,
* had a strong Church backing, including archbishops and Pope,
* called themselves devout patriots.