This sort of radical skepticism is generally unhelpful. It is simply not the case that the economics literature, on the whole, conveys no information. It conveys quite a bit, and often correctly answers a myriad of serious, useful, practical political questions. There are certainly edge cases that get a lot of attention upon which the data and consensus are split (e.g. minimum wage disemployment effects), but using those edge cases to disregard the research of an entire field (in favor of what, anyway?) is profoundly misguided.

Economic decisions have to be made by politicians. That is an unavoidable fact. They can either attempt to use the best data available to optimize the values that they care about...or they can just do whatever they feel is best, informed by, what? Their gut? Their down home common sense?