There are two main streams of moral traditions — one idealistic and absolute, the other relatively pragmatic and flexible. Each is a product of history and cultural perspective.
Absolutely, from God to Man
About six thousand years ago, God switched on the light, made things, and authorised humans to reign over them. Man was supposedly in charge of the world, which wasn’t exactly the entire universe — something we still don’t know much about, but pretend we do. Subsequently, God gave religious peoples the foundation of their moral codes. Nothing too complicated, but thou shalt not kill or steal is universally sensible, and works well if followed honestly.
Gradually, science nudges God off His throne. Humans take over, and steadily expand their God-given birthrights to reign over fish and birds. They march to conquer strange lands, funny heathens, the oceans, and nature in general, singing war songs.
Nonetheless, God’s exit has left an empty spot in their psyche, a vacancy which physics and chemistry can’t fill. After centuries of spiritual dependence, the urge to believe in something doesn’t go away easy. Moral excuses are needed to justify actions, many of which detrimental to themselves and others.
In cartoons, funny characters saw doggedly at the branch they’re perching on. In real life, Homo sapiens exploit their one and only living environment for short-term gains, and call it human achievement. Meanwhile, political ideologies have replaced religion, rationalising the killing and destruction of heathens. In man’s hand, morals have become more arbitrary, manipulative, and impractical.
And impractical ideals inevitably lead to hypocrisy and fanaticism.
Supporters of specious doctrines seldom “act as they preach” because, well, what they preach is not always practicable. But stepping back to rethink is sacrilegious. Moral principles are tautologically and absolutely good, uncompromisable. An ideal is a perfect end-point to strive for. Revising something perfect is yielding to the dark side, not incremental refinement. Unfortunately, to loyally defend untenable beliefs and infeasible ideas is the first step to fanaticism.