Please bring in rational argumentation and facts instead of just making claims about fiction.

From what we know, Auschwitz and Birkenau was/is located in very swampy land, with water levels coming up to just a few metres from the top, making it impossible to bury many bodies: they would rot and cause the ground water to get poisoned.

With the typhoid epidemic raging in the camp, there was a very serious and acute need for cremation ovens. These were not going to burn millions of bodies, but the hundreds and thousands of bodies of the inmates who died, from whatever reason: nobody claims the inmates were not used as slave labour and probably in very poor health conditions, as making sure so many people are properly fed and keep fit would be a daunting task for even the most humane and good-willing person: the fact of grouping so many people inside one barrack camp creates logistical problems on a massive scale already outside the setting of a country at war.

Now if someone claims that these cremation ovens were used to burn bodies who were gassed to death en masse, then that person has the burden of proof to show that the most logical and simple explanation is not true. And if the claims become so outlandish that it is quite easy to prove that the sheer amount of bodies to be treated are not possible in the given time span, then the outlandish claim should rationally and logically be dropped, instead of made a doctrine and its doubt outlawed.