Climate change deniers are a bit out of place in that group. While its pretty obvious to any sane person that climate change will (and in fact is) happening, we aren't yet to the point where it HAS happened (at least not in a big enough way to be obvious to anyone who wants to ignore science in the first place.)
Also, strongly suspect (and this may just be my own personal conspiracy theory) that most of the biggest/loudest climate change deniers are in league with the large energy and similar companies who stand to lose a lot if climate change regulation comes into play. Of course the loud (but "sane", in the selfish-I-just-want-money way) ones spark the idea in the actual crazies and it builds from there.
On the other hand, there is no such monetary incentive for anyone giving any fucks whether the universe was blinked into existence by a supernatural being 6k years ago or a multidimensional brane fart 14b years ago. People who choose to deny the evidence in favor of some arbitrary (and officially denied, assuming these folk are Catholic-derived and not some other Christian branch) interpretation of a 2000 year old book have no reason for their views other than being legitimate nutters.
Same with the holocaust. Except some of those people are still alive so the deniers are pretty much telling the people that watched their friends and families being abused, tortured and killed that its all in their heads. But the last of them will only be around another couple of decades at most and then there will be nothing but a terrible tale in the history books that hopefully future generations will take to heart and not repeat. The only people with any real incentive to deny the holocaust are those who might be called out for war crimes during that period.