Dear LekkoscPiwa, did I get it right?
I am sure you did not mean it that way but it might be interesting to know that many people would be seriously offended here if you included Russians into the perception of 'them' - people from outside of the Eastern block do not see internal differences important to people who lived inside - like the fact that 'Rusáci' occupied us for many years and are still perceived as the enemy by many people here. To make a simplified example to make it understandable - imagine someone talking about 'you western countries' and including example of 'your' behaviour - Nazi Germany.
The fact that Russia is possibly even more xenophobic than Poland doesn't change much.
I'm Belarussian myself, so well aware of sentiments in the 'hood in either direction. The nuance is not lost on me :)
Go to Arizona or California and tell me if it is difficult to find people who hate Latinos who don't make even such a big minorities there as Jews used to in pre-war Poland.
This has nothing to do with Jews specifically. Look at this how Arabs are treated in France (Paris) or London.
Once a group that has different language, religion, customs, and its own ghettos is large enough - my guess about 1/3 of total population - the natives will react the way the do. Poland or US, doesn't matter.