The deniers will move the goalpost, fabricate stories on failure, lie directly, etc. These people are mentally defective and use the process of first deciding how reality has to be and only then starting to look for evidence they are right. And when that evidence cannot be found, they just make crap up, because they are utterly convinced they are the smartest people around and whatever they think is right must be right. A complete failure of reality perception. I think this should be recognized as a severe mental disability and treated as such.