I hate this habit of referring to certain people as ‘deniers’.
“Deniers” are units of measure for the linear mass density of fibers. See the Wikipedia entry
Every time I see it I think of nylon stocking, the wartime and Americans ‘overpaid, oversexed and over here’. And I find myself pronouncing the word as ‘den-yer’, sort of, definitely not as ‘de-nigh-er’ which is what is wanted, I assume.
The word they are looking for is ‘denialist’. Again, see the Wikipedia entry.