The history is that during the Soviet era, Ukraine was mostly seen as an "extension of Russia", Belarus as well, however I'm not familiar with Belarusian left-wing nationlist figures and history. The individual presented in the picture is Olexander Shumsky who was a Ukrainian left-wing nationalist who heavily defended it's independence and was quite hostile to the Kremlin's decisions under Lenin and Stalin that tried to put it back into a colony state while they constantly preached "national self-determination". But he also went against Central and Entente powers who he viewed as imperialist as well. Shumsky here is defending Ukraine against any form of imperialism that tried to get Ukraine in their sphere of influence or to install a puppet regime (which happened with the Hetmanate ran by Pavlo Skoropadsky who was supported by the Germans against the Ukrainian People's Republic, a social democratic/democratic socialist state).
