Every nation has national interests. The point is that advancing them by subjugating another nation is wrong; ask a Pole about the old Soviets. There IS a difference between “them” and “us.”

BUT – you are just describing the differences between the ideologies between the two countries. Stalin was a dictator of a Marxist-Leninist state, intent on centralised control of its population and belief in a state managed economy. That is precisely how they operated, and Poland was no exception. Churchill’s Britain, based on a liberal democratic ideology was of course not going to actively ‘force’ the Greek decisionmakers into policy that would favor the British. (Although the troops sent in after the 1944 conference to fight the Communist faction in Greece, was essentially pushing the country towards keeping a democratic government).

Arguments made over the difference of national interest are ideological, and therefore the original question of whether they were the same in essence is arguably yes. Both were dominated by self-interest, the intent of both Churchill and Stalin being similar in both instances. Both wanted influence in each country, and their own ideology to be stamped on it, for both economic and security reasoning. Just their ideologies went about and implemented their objectives differently.