I imagine it's comparable to the damage done when policies are set that are not based on studies.

Let's be candid: Most policies have no backing in science whatsoever. The fact that some were backed by poor science is not an indictment of much.

From a political point of view, it may actually be beneficial for a policy to have no scientific basis. What happens when the science gets updated?

You either have to change the policy and admit you were "wrong" to an electorate who can't understand nuance, or continue with the policy and accept a few bad news days before the media cycle resets to something else.