As much as NormalRussian is coming off as a provocator, I have to agree with what he is saying with the Ukrainians. It is FACT, that they served in special SS units and stabbed Poles in the back, murdered, pillaged, raped, the Poles living in the East.
Ukrainians have never been "perfect" example of a friendly Slavic country to Poles. Poles have always had to deal with these barbarian Kossaks. That will never change.
However, NormalRussian, when you said that Poles concentrate on Katyn rather than Ukrainian SS units, you are wrong. This is well known, and both issues have been discussed. Russians were in fact, a lot worse than Ukrainians with their peace treaty with Hitler in 39' to eat up the rest of Poland in the east.