I can rationally explain how the gas chambers, pits and cremations worked.
I am sure you believe that your explanations are rational; however, to a person with some engineering skills and scientific acumen those explanation fall woefully short of reality. Perhaps you can explain why the American use the following for a gas chamber, which appears well engineered and technical.
US gas chamber for executions
While the Nazis who were technically superior in aspects of gas chemistry would use the following or something similar.
Don't you think this is just a little too crude, unlikely to do the job of mass extermination of bugs lets alone people.