Being helpful

Another notable thing about that BBC website article is the attitude of the Polish government towards Ukraine vs Russia:

"The Kremlin accused Poland of engaging in anti-Russian 'hysteria' after Polish Foreign Minister Grzegorz Schetyna credited Ukrainian soldiers, rather than the Soviet army, with liberating Auschwitz."

Obviously the current situation between Ukraine and Russia plays a part, and obviously Poland has a very long history of problems with Russia: just looking at the 20th Century, a big chunk of what's now Poland was a puppet state of the Russian empire (for about a century prior to the end of WWI, the rest was part of Prussia / Germany); the Russian army failed to protect it against Germany and Austria-Hungary during that war; there was a war between the newly reborn Polish state and the Red Army in the 1920s that Poland came very close to losing before winning via by taking advantage of a gap between the two army groups sent against it;* the Soviet Union invaded Poland in September 1939, killing tens of thousands of Polish leaders; in 1944, the Soviet Union failed to assist the Polish uprising against the Germans in any meaningful manner, then imposed a communist puppet government; and Poles take zero comfort in the way that that was probably the 'least worst' such government in Eastern Europe, blaming Russia for decades of oppression, mass arrests, torture, low living standards etc etc.

But the majority of the staff at the extermination camps were Hiwis - 'those willing to help' - and typically Ukrainian...

* _{This is a big reason why Britain allied with Poland before WWII - as well as not being communist, it was seen as more effective militarily. If Britain had allied with the Soviet Union instead, they'd have been no Molotov–Ribbentrop Pact between the Soviet Union and Germany to secretly divide up Poland and possibly no German invasion of Poland...}