Well, it potentially does make it “ok” in the sense of being less bad than letting the guy off. That’s why the legal concept exists. There are other contexts where there is no good faith exception, but in this situation there is one.

In this case the crime is a bank robbery which isn’t victimless but most people think of as somewhat “victim-lite”. If the crime was the stranger rape of a little girl then the vast majority of people would have been outraged if the police had not obtained this warrant.