You're really a dunce, aren't you, Hawkeye?
How to you explain the testimony of thousands of people who were in those camps, including many German guards?
Research it. Every time the guards told the truth, they were tortured, threatened with hanging, and/or had their families threatened. Most quickly learned to figure out what testimony was desired of them. Some of the camp personnel went to the noose insisting that they did everything humanly possible to prevent the disasters in the camps, but had no supplies with which to do anything, despite repeated requests for same.
As for the testimony of the prisoners, they were indeed in camps. Their mere survival, however (in astronomical numbers, no less), suggests that either the Germans were the most inefficient people on earth, or that there was no operation to eliminate the Jews.