I don't find it strange it all (though the info about the offer caught me by surprise as well). Mass deportation was not very popular anymore back then. But this would have been the only option to make this area actually attractive. A run down area full of poor Russians - the only worth detectable is of an sentimental kind. Realpolitiks on the other hand say: Don't even think about it! I said it hurts to see what this place has become. But when Germany had the chance to reach out again, it already was what it was. Well the SU could just not have decided to shift Poland 200 kilometers into the West.