Can you also be imprisoned for saying 2+2=5?

David Irving has been sentenced to three years in jail in Austria for denying the holocaust while he was there in 1989. Beside Mahmoud Ahmadinejad, who does this help? It is true that the only people who deny the holocaust are antisemites, but treating this historical event differently than any other event just fuels their fire. The state prosecuter claims that Irving has been treated as a martyr by right-wing extremist groups. Well, maybe if the state dismissed him as the nutcase that he is, then these people wouldn't have any grounds on which to do this.