The invalid doctrine of post-modernism (Relativism by a different name smells as foul) has beome popular and resulted in dumbing down of popular culture
Depends what you mean by good, Muhammad was undoubtedly a good war lord, a good general. But does he rank as morally good? Who is to judge, not you or I. But of what we know of his life it does not stand out as morally praiseworthy and some of his actions seem morally reprehensible