Science does not lead inexorably to policy. Science is only the first step, in how it allows us to understand the world around us. What we want to do about that is an entirely value-based decision. Deciding to implement policy demands filtering that understanding through a lens of our collective values as a society. Those values are fluid, and very frequently in controversy. It seems like the demands to "follow science" are an attempt to sweep some of that controversy under the carpet.
In the case of climate change, it's pretending that there's cost/benefit analysis to be done. It ignores the possibility that the cost of doing something will exceed the likely damage expected. (I'm not saying that's the case, I'm just saying that folks are trying to skip that part of the conversation)
It pops up in other cases, too. Virtually every economist will tell you that free trade is almost always a net positive for all involved. It harms a few, but on net the entire society is much better off. If we stopped with the science, then we should remove all tariffs and be done with it. But before we do so, there's still a moral question to be resolved: if a few people are paying the price to improve our overall economy, do we owe any debt to them, to make them whole afterwards?
So stop pretending that a lack of the policy you want demonstrates that we're scientifically illiterate. Instead, recognize that the science can only inform our debate over the values.