Right. Note that Stepan Bandera was in Nazi prison at the time and likely would have disapproved of them if he could exercise control of OUN-B at the time.
There is no denying that OUN — both fractions — saw Poland and the Soviet Union as main enemy, were willing to collaborate with the Nazis when they saw it in the Ukrainian national interest, and committed atrocities and ethnic cleansing like virtually any other participant in the German-Soviet War of 1941-45.
Similarly, the Sovs collaborated with the Nazis when it gave then an opportunity to invade Poland and the Balt states, burned their own villages in retreat, condemning them to death of starvation, massacred an untold number of Poles and Balts, raped their way through Germany, deported whole nations to Siberia and enslaved the Eastern Europe for 40 years. In doing so they did no favors to their own titular Russian nation which still bears the scars of the Soviet Power. So your point was?
I repeat, it is extremely noble of Poland to support Ukrainian Nationalists in their desire to build independent Ukraine, despite the history between the two nations that you point out.