Ya see Saggy, you have nothing, never had. You have a self replicating argument. If the gas chamber had been left as it was the day the last gassing took place, it wouldn't be there anymore - then the argument would be - Oh well there is no evidence.
The people who maintained the site for the first 50 years didn't know they were meant to be maintaining an evidence locker for people like you. It is a memorial to the people who suffered in its confines, nothing more. The world knows what happened there, the site has been picked clean of anything useful to future generations. Nobody wants to have a working death camp, they dont need one, they have all the evidence they can ever comprehend, they know how it worked, they understand the process, in reality they just want it to go away.
Unless huge amounts of money are poured into the site, it will be gone in our lifetime. Who wants to put such money into a project that will do no more than show the bastardry man can bring on himself. There was no noble outcome, no glorious victory by man against a threat, all that is left is the stench of death, great sadness and a stain on our consiousness that will take generations to heal.
Or so you tell us repeatedly