While Mel Gibson admitted that “some” Jews died in concentration camps, his answer to his father's rationale that the Germans just couldn't have possibly killed that many, they didn't have enough gas, most fled, etc - was that “My father never lied to me”.
But I guess no bridge is a bridge to far for “Saint Mel” for some people.
He said stupid things and made himself look like an idiot, now even other Hollywood idiots don't want to work with him.
He has nobody to blame but himself (and possibly his father, who taught him so much that was supposedly never a lie).
The context was an badgering interview trying to make him denounce his father. He was obviously uncomfortable with entire line of questioning and gave ambiguous responses. Your piecing together a "denial" in this context is an attempt to read the man's soul.
You may think you have reason to suspect that Mel doubts the six million figure but to say the he "denied the Holocaust" is patently false.