For one species, sure, for 35 you have to wonder how ideologically driven you have to be to keep blaming the environment. We're at tobacco companies in the 90s level of denialism here.
The thing about climate change in prehistory is that it drives changes to human life. Archaeologists put glacial maxima on their timelines because it's such an important factor when trying to understanding human migration, the spread of new technologies that do better in drier or wetter climates, the shift to different food sources, and so on. This predates the current climate-aware political landscape.
If 90% of a species is killed off by climate change, and if for hundreds of thousands of years that species survived glacial maxima in reservoir populations in areas that are now populated by starving humans who kill the remaining 10%, was it the climate or the humans who wiped out the species? The changing climate killed more, but the humans were the differentiating factor, so which one do you point the finger at?
I don't think it's right to call that denialism.
If we're the differentiating factor, I'd have to blame us. Am I right in understanding that these species were normally being thinned during each glacial maxima, such that it was already a set part of their evolutionary environment? If that's right, then aren't we the ones to blame?
Otherwise, is a murderer merely a "contributing cause" to someone's death if the victim happens to be sick at the time of the killing?
My main point was that I don't think it would be denialism for someone to say "no, the species was pushed to the brink by climate change anyway, we know other species went extinct prior to human colonisation, and even though humans arguably made it worse there's no conclusive evidence". Glacial maxima are hundreds of thousands of years apart and given the timescales involved it's hard to say whether a species is adapted to them or whether it just got lucky.