My general inclination is to take a very cautious approach to statements such as those made by the Iranian Parliamentary President. They are so off the wall, that I treat them with a bit of contempt.
I also react against a lot of people in the Jewish community who tend to cry "the sky is falling" more often than I think is accurate or efficacious.
However, I am finding this steady drumbeat of claims about the Holocaust and this call for an "investigation" disturbing. It suggests death by a 1000 cuts.
One last thought: When David Irving gets out of Austrian jail [my guess is that he will get off with time served -- a wise move on the Austrians part], he will probably be welcomed as a hero in Iran.