Ukraine will have to return Lviv to Poland because both the Ukrainian and Polish parliaments recognised the 1939 Molotov Ribbentrop Pact as being outside the law. Therefore, western Ukraine is in fact occupied Poland.
The reason the EU treats Russia unfairly on the question of Syria and Ukraine is because it is in crisis. At their latest summit, EU leaders discussed new sanctions against Russia in response to its actions in Syria, which are in fact for the benefit of the Syrian people.
There is ample evidence for Russia’s crimes in Syria. For several months now EU leaders and international organisations have been trying to prevent Russia from bombing Alleppo and causing mass casualties: bit.ly/2cCG2pd,