I'm not entirely certain that simple holocaust denial was the cause of problems there. It could be that specific claims were the problem rather than more general holocaust denial claims. I'm not familiar with these cases in particular, however.

I do have some issues accepting a holocaust denial position. More specifically, I have reviewed a lot of the information for myself including two different eyewitnesses and I find their conclusions difficult to support given the evidence that does exist. Sure, I do have issues with it being characterized as an exclusively Jewish thing, somewhere between a half and two thirds of the victims (depending upon how you define the Holocaust relative to other programs of repression) were Poles, Catholic Clergy, Gypsies, political rivals, communists, speakers of Esperanto, the mentally disabled, and homosexuals. Organized political violence, particularly comprehensive and meticulously planned political violence, is fundamentally bad and shouldn't be white washed by anyone.