EDIT: The statement can be removed just on the basis that it adds no value to the article by making it even more biased towards enabling the Holocaust all over wikipedia. It assumes that - Leuchter doesn't know the amounts of cyanide needed to kill, and it assumes that Leuchter tried to disprove the gas chambers through ignoring the facts. Both of these without any proof that that's actually the case. 

Also, even if that was the case - what does "tended to confirm it" mean? Even safe amounts of gas found by any interested parties would "tend to confirm" that gassings took place, so it's irrelevant.

In general, the whole article is focused on disproving the Leuchter report instead of displaying the Leutcher report - that's why it needs to be rewritten.