What if (for the sake of the argukent) they are accidentally right? I.e. despite a clear bias they reach the right conclusion that and indeed the effect of climate change is negligible as a causal agent in this case. Dismissing that possibility just because is supported by those who would support it no matter what (and furthermore backed what whatever ulterior motive there might be) is no different from what others ascribe to the environmentalist camp, labeling it just as political activism leveraging anything that happens on the world as a proof that they are right.

Don't get me wrong, I do have my own opinion about what's going on that I built using more or less the logic you described. But if I step back I see it has to be driven by by own biases, otherwise how would other reasonable people come to other conclusions. I wish there was more we can do to make it easier to discuss such topics between people who come from different starting points.