A better example would have been their Slavic neighbors, Slovakia. Hitler made Slovakia a puppet state, when Czechoslovakia was broken up, and appointed a Catholic, Josef Tiso as the leader. As a result, for the most part, Slovaks were treated much better than the Poles by the Germans, although they were considered untermenschen Slavs.
One of the interesting things, was that Hitler ordered an honor guard around Pilsudski's grave when the Nazis invaded in 1939....which leads to the question, what if Pilsudski was still leading Poland in 1939?
Another theory was that the Nazis, according to their racial theories, feared Poles, because they thought that while they were Slavs, many of them also possessed German blood, which would make them tough fighters, and would continuously be a threat to the Reich, if they weren't eliminated. This would explain why Poles were especially singled out amongst the Slavic peoples. Which would also explain why the Nazis would never have considered using Poles as guards in the death camps, as opposed to Ukrainians, knowing that if they gave a Pole a rifle, they would immediately use it on the Germans.
I think it was less due to blood and more due to history.