There’s nothing wrong with unit tests per se. There’s something seriously wrong with people solely relying on them, assuming that the program built from pieces each of which passes an unit test, will be bug-free. Or, better said, these people are badly misguided, forgetting that unit tests are just part of the the wast world of testing - integration tests, functional tests, performance tests, stress tests, carry on.
I think that the best advice for unit test zealots would be just to go out and buy (or download 
any book on software testing, take a time to read it, and open their eyes to the whole world they’ve been ignoring.