It is ignorant and dangerous, and it flies in the face of all we know about Germany's immaculate record keeping and attention to detail. They weren't making this stuff up. If only they were.
What's more, Germany itself does not deny what happened in the Nazi era. It has had the courage to face the truth rather than try to peddle alternative facts.
Maybe many people today have never known a Jewish person, but I have known many since childhood.
My mother worked with and befriended Jewish people who managed to get to this country before it was too late, and there were always Jewish people at school with me.
Being young, the only valid excuse for obtuseness, it never seemed real to me that their families had likely been murdered in concentration camps.
It's one thing to know because you're told, but another to internalise and believe it. Those classmates were young like me, and the subject never came up.
How could it? But that burden of knowledge must rest on Jewish people to this day, religious or otherwise.
That is why Israel exists. It has been a clumsy way of trying to right the wrongs Jews suffered with the collusion of all the countries the Nazis invaded, as well as of right wing thinkers in England and elsewhere who loved that fascist trains ran on time. To the death camps and elsewhere.
The bright idea of giving Jews a haven has proved illusory. Like so many compassionate ideas it has attracted ugliness, so that visiting Iranian cleric Hojatoleslam Shafie could falsely still claim in my country that Israel "hides behind a fake phenomenon" of the Holocaust.
Holocaust denial puzzles me. What would it mean for the Iranian envoy, Hormoz Ghahremani, if he accepted that it was true? Would it mean he could no longer advocate Israel's "surgical removal"? And what then?
The bottom line for the conduct of the diplomatic corps abroad should be civility and tact. Diplomats may not agree with the way we live, or cherish the same beliefs, but the point of mixing with people from other cultures is that there is a benefit both ways.
Using our tolerance - which their own countries do not share - to voice extreme and hateful views is abuse of our hospitality.
I'd like to think Ghahremani would realise that he should voluntarily return to where his bigotry is appreciated.
He may argue that a mosque is a private place where views can be freely expressed, but he knows very well that opposing points of view will never be heard there, and that mosques and churches are open to the public in the free world with no secret handshake at the door.
More than that, it is slinking and craven to imagine it could ever be right to brew hatred in secret places.
My generation, who grew up in the shadow of World War II, won't buy into lies about it. But it troubles me that later generations may come to accept falsehoods simply because they're so often repeated.
Today we enjoy the ethnic diversity that is transforming our country.
I remember the impact of Jewish immigrants and refugees on a country that had revelled in its own blandness.
We owe those people a debt best paid by honouring the rights of all minorities, and shielding them from harm.
Rosemary McLeod is a journalist and author.
