Most people haven't read the original untranslated versions in order to understand them better, but a lot of academics, such as classics professors, have. I've learned about Greek culture from a few professors who would discuss at length how the Greek conceptions of, say, honor or cunning differed from our modern conceptions. But if they were also of the impression that the ancient and classical Greeks did not have a concept of morality, then that would have been a very conspicuous and relevant omission from their instruction. So I'm inclined to suspect that this is a minority interpretation.