It certainly does hurt the credibility of people saying we need drastic changes now based upon the models. If the answer might change next year, then making a drastic change based upon the current projections seems foolhardy.
We have known the rough level of the climate sensitivity (delta T per doubling CO2) in the current macro state for decades. We have observed it. This science is incredibly settled. We don't know where the tipping elements are and we don't know how the impacts will be distributed.
Questioning the credibility of people calling for action might look like you are being the circumspect and rational one, asking for action proportionate to the evidence. In reality you are endorsing an ignorant position that ignores the evidence we have. If this is not wilful ignorance then please read up on this. The IPCC report summary is a good spot to start. Sceptical Science also often provides good writeups: https://skepticalscience.com/climate-sensitivity.htm
The fundamental physics that drive the sensitivity are straightforward. Energy balance and water vapour. That gets you a ballpark figure that is confirmed by the last 100 years of emissions.
It is a denier talking point to claim that we just don't know enough, or that the models are always being tweaked and we should just wait until scientists have "the final answer" before doing anything.
Hey, let's stop giving NOAA weather forecasts because they aren't 100% accurate. Let's close down the stock market until everyone can decide what the values should be. Let's disband the military because not all military leaders have the same opinion.
If we are mature enough to recognize that imperfect but credible models are worth acting on in other domains, why do we hold climate change to impossible standards?
What you're saying is that you have established a prior that undermines all further evidence presented to you, because it has changed substantially in the past. However, that seems irrational to me.
Given that, how could you possibly advocate for doing nothing?
There are two basic modes of reducing pollution. Technological advancement, and conservation.
In the case of technological advancement, you get less pollution per unit of output as the same or lower cost. As long as capital is fairly cheap, these advances tend to propagate quickly through a competitive market.
In the case of conservation, it’s more a question of which groups of people should conserve (i.e. suffer) for this outcome, and by how much.
I'm seriously wondering why there is any reason to oppose technological progress at all. What can they possibly gain by sticking to the old technology? Who's going to benefit from something so short sighted?