I don’t know where your stance is but AFAIK dark matter is not an established fact. In fact, nobody has ever proved the existence of dark matter, not to mention describing its properties or even seen it. Very recently, a research paper made the round with the claim that in very low acceleration, the gravity force works more like MOND and not as Newton or Einstein described. One consequence of such observations is the inconsequence (no need) of dark matter, but the need for a new/modified law of gravity. Would you call such authors “denier”?
The very essence of science is to (able to) denied itself, once discrepancies between theory and observation appear. Every scientific theory in history has been and will be proved wrong, making place for a better one. Every! And that’s science. Otherwise, I’ll call it doctrine or religion.
I’m very much for fighting the climate change (and consequently believe in its anthropogenic cause). But I welcome anyone who can scientifically disprove it, meaning with facts, logic and falsifiable theory.