You can say it would’ve been more efficacious, but I have no idea what you base that upon. It’s not as if shipping cost is the only concern. Mass murder has rather more complex considerations than selling widgets, ir whatever it is you’re comparing it to.
I think it had a lot less to to with antisemitism in Poland than it had to do with hiding it from western Europe. After all, convincing the French to put them on a train for “relocation” is one thing convincing them to put them on a train headed for extermination is a whole different ball game.
Of all the combatants in that war, Russia would have had the least problem with the death camps.
As a nation and a people, Poland probably got the worst of that war from both the Nazis and the Russians. Both sides were conscripting their children as soldiers and slaves.Something like 17% of the civilian population of Poland was killed in WWII (5,620,000 to 5,820,000 people)
http://en.wikipedia.org/wiki/World_War_II_casualties
In any case, Auschwitz was in the General Gouvernment, territory under direct German rule that had virtually been annexed by Germany and only a short distance from what had been Germany proper.
The prewar Jewish population of Europe was overwhelmingly East of Germany. It was not hard for the Germany to kill off much of the Western European Jewish population without establishing death camps in the West.
Also, the Germans may have shared the common idea that the East was already savage and that mass murder wouldn't have aroused any protest there, and would have in the West. As it was, aside from Denmark, mass deportations and imprisonment didn't arouse protests in the Wests.
When peoples live separately but side by side for centuries, relations can be complicated and difficult. Your oversimplifications, though, don't help untangle things.