Right, I’m fed up. If you try and play for cheap laughs by messing around my screen name, achiv ani berama’uso:
nishtinganzenkop – It is an ad hominem attack because you attack the person, not the argument. If, as you believe, the story is untrue there is no need to say it in a manner which is directed at the individual. You could, for example, simply say “in my experience of shochtim I have never come across such a thing, but I do know etc.”. This would then present your point of view and expose what you believe to be false without resorting to name calling. In addition, you would have to bring some form of evidence to back up your claim; simply saying “you’re a liar” just isn’t good enough.