Macroeconomics isn't so much a religion as it is a pantheon of religions. Religion and spirituality are really separate things. Jainism, Buddhism, Daoism, and Confucianism are religions, but they worship no deities. Religions just try to explain how the world works and how to make the existence of its members better. Communism, Keynesianism, and Nazism do the same thing.

Few Western economists think they know all the answers. Saying economists are wrong to try to estimate what the economy will do if some policy is enacted is like saying that biologists shouldn't try to estimate what will happen to a human body if a certain drug is administered. Of course, no one will know for sure how someone will react to the drug as there are a million different factors that influence such things. But, it's best to do your best to try to figure out if something is going to be poisonous based on all the things you know about the human body and chemistry before you give it to the patient, right? Economics is hard because you can't do repeated trials. Most economists acknowledge this, and they understand the pitfalls of their craft. There are plenty of instances of individual economists making outrageous predictions about the future that proved comically false. But these are the exception, not the rule.

The problem we have now is that politicians think they do have all the answers. The Republican party has decided all that is needed for economic growth is lower taxes (not low taxes, mind you--lowER taxes). The Democrats, likewise, think all you need to do is throw money at a problem, or regulate it, and it will be fixed. They KNOW the solution and they won't consider any other solution because they already have the answer. I wish just one politician would say "I don't know" and would ask economists what is likely to work under the circumstances.