Why? They formulate theories and test them against data to understand how the world works. Is that not the definition of science?
Economists aren't uncovering an underlying truth, they're basically building toy models. These toy models might approximate economic systems in a narrow range of controlled circumstances, but things rapidly deteriorate outside that range. The problem is that people assume the models reflect reality, and make bets based on that assumption.
It would be nice if economists focused on fully Bayesian models with Gaussian process priors and long tailed (ideally Levy alpha-stable with a low alpha bias) likelihood functions. At least then the uncertainty of their models would be absolutely clear, and black swan type events would be partially factored in.
No, in fact they don't. It's hard to believe, I know.