history is never one-sided like hand-picking of facts and interpretations tends to present. Together with the "occupation by Russia" Poland also got to annex significant parts of German territories (some of those had had no valid Polish claim, like for example the Prussia, some had been historically contested between German and Poland) - it was practically spoils of war gifted by the "Russian occupiers" to Poland (any gratitude for the gift?). The "occupation" has ended 30 years ago, and that is basically a right thing. Any plans on giving the annexed territories back?