When the honest man is caught in some crime, he meekly confesses his part in the matter and (hopefully) turns away from doing the bad thing again.
When the hypocrite is caught in some crime (particularly what they have been so quick to judge in others) they never admit to wrong-doing, but they always clothe their evil and crimes with some honest presence or pretended good reason. So the hypocrite has been regarded throughout history as the vilest person.