True. And it's a strawman argument. Nobody said that with science you get the best objective decision. However, you can make the best with the knowledge available at the moment, and that is constantly changing.

I really don't see why people have such a difficulty understanding the basics of the scientific method. Science tells you what is the best up to that point, with the information available. As more information comes in, you make better predictions, create better theories and better experiments. It's not a fallacy of the method, it's how it's supposed to work.

When the first ideas of non-Euclidean geometry were introduced, we didn't throw geometry out of the window. We gained more knowledge. When Einstein proposed the theory of relativity, we didn't burn the books about Newtonian mechanics.

Why do you keep thinking in absolute, philosophical terms? If you want to better manage a society, you need to be practical and talk about real things.