Sure they realize that. They also realize that Hitler invaded them in alliance with Stalin, that Stalin proceeded to kill hundreds of thousands of them in less than two years (a faster pace than Hitler at that point), and while the second coming of the Red Army wasn't as bloody, and it sure as hell was better than the Germans, it still wasn't gentle. Then they stayed for almost half a century. And it was only twenty years before WWII that Poland had become independent - with the bulk of Poles under Russian rule during the Partition perid.

Liberation is nice, but it doesn't outweigh the rest. The Czechs, Hungarians, and Slovaks only have the latter part of this history, so less suspicion. (The Hungarians got the Russians in 1848, but they left immediately and two decades later they got the Ausgleich)