>>the same people moving the goal posts
Perhaps, but I see this from the pro-climate-change side, too. First it was a "coming ice age" (1970s) then it was Al Gore banging the "global warming" drums (1990s), now it's simply "climate change" (either/or) -- "heads I win, tails you lose." It's intellectually dishonest.
There is a very important reason to inquire as to whether mankind is the cause of global-warming, or merely an observer. If man is the cause, then perhaps there is a chance to prevent it; we might ask what action might one take. If man is merely the observer (e.g. the sun is to blame) then our odds are infinitesimally small for having any positive effect whatsoever, and quite large for having unintended consequences.
It is not "denial" to ask for evidence, untainted by politics or opinion or data clouded by curve fitting and backwards adjustments to "compensate" for who-knows-what but always in a way that predicts gloom and doom and fosters continued grant money. That raises suspicion of any open-minded person and especially the cynical.
Personally, the groupthink hysteria surrounding this "settled science" alarms me much more than the .5 degree C/century temperature increase observed. I have lived long enough to remember the panic about the world starving to death in the 60s, the coming ice age predicted in the 70s, and recall scientists literally laughing about the idea of bacteria being responsible for ulcers, high-fat diets being "deadly", cholesterol and salt is bad for you, etc. Trends change and science moves ahead, often not hand-in-hand.
finally, you should drop the ugly "denier" label. lumping in those who ask for evidence for global temperature change with those who deny the occurrence of the holocaust is sickening and has no place in reasonable discourse.
(edit:fixed typos, and formatting)