Obviously, you did read what I wrote. So, I will say it again!
You make a deal with a devil to fight a greater devil. The lesser devil will make you do devilish things. Much like an urban gang will make you commit a random killing as a rite of initiation.
Eastern\Central Europe has 100s if not 1000s of years of ethnic hatreds that a Hitler could easily exploit with a Bandera and others like him. The Poles & Ukrainians have a dislike for each other that not only stems from religious differences (Catholic vs Orthodox) to memories of wars & atrocities (both sides!) between Ukraine & the Polish-Lithuanian Commonwealth (circa 1600s) to the Czarist use of Cossacks (Ukrainians) to enforce Russian Imperial rule in Poland. I think they may now be past that perhaps thanks to the current war.
The history of all those countries and ethnicities is mostly bloody tragedy! In the Eastern\Central Europe, the Balkans massacres, mass enslavements even though they happened 500-600 years ago are kept alive like they were yesterday. It’s foolish to judge the countries, the cultures through a modern Western cultural lens.
I no way can anything I have written imply I approve of such actions.
Your analysis and historical knowledge is correct...but...
There’s one thing that all those mutually antagonistic, feuding ethnic groups all believed and agreed on—IT SURE IS FUN AND PERFECTLY ACCEPTABLE TO KILL JEWS! THE UKRAINIANS ARE ALL FOR THE OLD TRADITION!