If he is a joke,why is he in prison?
He's viewed as a joke by the vast majority of historians. My best friend's grandmother is a very famous holocaust survivor who gives talks in London. She was asked to enter in to a debate with him, she refused on the grounds that entering such a debate (whether the holocaust actually occurred or not) simply legitimizes it.
Irving is in prison because, as you alluded to, holocaust denial is illegal in certain countries. His work is debated then (correctly) dismissed in English universities. The reason for this is that it is historically inaccurate.
If I argued that Hitler never invaded Poland, should my historical work be given any credence? Would it be debated in universities? The answer is no because it is bollocks, as is the ramblings of holocaust deniers.
Any intelligent person who has studied history will tell you this!
German Sentenced to 10 Months for Hitler Greeting
'A judge called Horst Mahler "utterly incorrigible" after he denied the Holocaust, again, in open court.'
'Charges against Mahler include sedition, using gestures of an anti-constitutional organization and criminal insult. Holocaust denial in Germany falls under the crime of sedition, or Volksverhetzung, because it's regarded as an incitement against Jews as an ethnic group.'
As i said, holcaust denial is illegal in some countries, thus the prison sentence. This man is clearly a Nazi which I think enforces my argument about the non-historical anti-semitic agenda of deniers.
This is not historical debate, it is not a quest for knowledge. We shouldn't even consider talking about it.