Yes, but the evidence for what?
Most Holocaust deniers don’t deny that Jews were rounded up and put into work camps. What they deny is that there was a systematic, organized attempt to exterminate the Jewish population.
And while the Holocaust is, as you say, well-documented, the deniers use that evidence to support their cause. They point to eyewitness accounts and how they different on a variety of subjects (as all eyewitness accounts do, especially when they’re recollections years after the fact) and use those differences to ‘prove’ that the eyewitnesses are actually making it all up, or that their memory of anything should be considered flawed. The point to the recovered instruments of death- the gas showers, the incinerators- and use experts like the aforementioned Leuchter to ‘prove’ that those instruments never could actually be used for mass murder- why, the pipes are too small and too far apart to ventilate in the way necessary. Ergo, no gas showers.
When there is so much evidence of everything, specific facts are easy to cherry pick. And so the Holocaust deniers cherry pick those facts which prove that there couldn’t have been a systematic effort to murder the ‘objectionable’; all that happened was that the Jews were rounded up and placed into work camps, where due to malnutrition and Allied bombing- which the general public was subject to as well, the denier will remind you- many of them unfortunately perished.
After all, the denier asks- do you believe that human beings could be so fundamentally evil that when fanatics took over the government and rounded up the Jews with specific intent to murder them, the German populace simply turned the other direction, indicating that tens, maybe hundreds of thousands of everyday people like you and me simply accepted the incineration of their neighbors without even a shrug or a squawk to the newspapers or any sort of protests… or, would you rather believe that an organized lobby with its own agenda turned a tragedy into tales of mass murder in order to gain victim status and ensure the creation of Israel? Which is easier, the denier asks, to believe?
Unfortunately for us, we know which one is actually correct.