Well if that's true then it's definitely below the belt. I think it's safe to say that something very insulting was said to Zidane which made Zidane snap. Just because he's a professional footballer doesn't mean he's any more thick skinned when it comes to matters like this. And where was Materazzi's professionalism when he said whatever it was he said? There is a line you just don't cross, whether you're on the pitch or the street. If Materazzi crossed that line then he deserves what he got and I don't blame ZiZou for what he did.
Or maybe Materazzi said **** all and Zidane just wanted to create a bad boy image for himself after seeing the success of a certain Mr Vinnie Jones
