A gratuitous assertion - which doesn’t alter the fact that religion is based on the rational belief that persons are not purposeless freaks.
BTW What was your other reason for inferring that others hold the same value for their lives apart from physical similarity?
Where are these ‘objective’ values and purposes to be found and observed?
In the immense value and purpose of a rational, autonomous existence which is designed - and not a freak of nature.
Do you know how recent in our history the UDHR was formulated and ratified?
Irrelevant.
Humans kill unnecessarily even when they think it’s necessary…
Why “even”?

.
…often because someone else told them to do so, or indoctrinated them to believe that some people should not be suffered to live, or are merely expendable.
That doesn’t alter the fact that many kill unnecessarily because they reject any higher authority and worship themselves…
Self-interest is not synonymous with selfishness.
Never said it was.
You implied it.
Expediency itself is rational. It’s all about doing what needs to be done with such resources as are available.
Expediency is indeed rational - if you are prepared to use any means to achieve your goal.
So you admit that religion is a human invention…?
Religion is the discovery that we don’t exist merely to save our own skins.
I might not consider myself answerable to an imaginary deity, but I am nonetheless responsible for my actions and answerable to those who are affected by them.
Having rejected religion because it was an obstacle why brook any other obstacle?
I don’t believe I may simply do as I please with no accountability.
Who or what decides whether you are accountable?!
What’s the good of a belief that doesn’t have any bearing on one’s actions?
None whatsoever. That’s why they are hypocrites!
Metaphysics is an exercise in building castles in the air, as far as I can see.
What do you think science is based on?
Did I neglect to mention the corrupting effects of civilisation?
So the UDHR has corrupting effects?
How can I when the law of the jungle prevails in the political, financial and economic institutions in this world? Bestiality has more than one meaning…
All highly civilised institutions, I might add…
Institutions - corrupted by individuals - on which you rely for security and the freedom to criticise civilisation…
Humans cannot but live like animals when they are convinced they are animals - as we see from the sick society in which we live - which you blame on civilisation!
You have just indicated that you see many of the signs of corruption inherent in civilised societies. If we lived more like the animals we are, many of these sicknesses would abate.
Your faith in bestiality is irrational.
Freaks of nature can live only in accordance with natural causes.
What’s your point? That you think we’re somehow ‘better’ than nature?
‘better’ is a meaningless term in the natural world.
That’ we’re not ultimately part of it?
If you’re part of nature all your behaviour is determined by natural laws which preclude the ability to choose what to believe and how to behave.
Find me the rules in the UDHR which stipulate the obligation to promote the destruction of the environment. Such is the success of the secular foundation of morality with its futile appeal to empathy, faith in the social contract and the realisation that people can only gain through reciprocity!
The innate morality we possess as a species is corrupted by the stresses of civilised society.
What archaeological evidence is there for “innate morality” in prehistoric man?
That’s why we’ve had to keep inventing things like religions and international treaties to keep ourselves toeing the line. We’ve detached ourselves so far from our true nature that we’ve forgotten how to live except by lists of rules.
Your faith in the noble savage is unsupported by archaeological evidence. It seems the pantheistic equivalent of the fundamentalist’s Garden of Eden…
You must be unaware that the exaltation of natural selection as the primary cause of development is rejected by many scientists.
Debated, I think you’ll find - not rejected.
Certainly not established…
You may find it instructive to remember that the lives of our earliest ancestors was dominated by a struggle for food and competition for resources in a harsh world in which the most ruthless dominated the scene and survived by brute force and cunning - without pausing to ask questions for the simple reason that they were incapable of speech, syntactic communication and diplomatic overtures…
Wow - that tirade could have come straight from Stephen Pinker.
An ad hominem which doesn’t alter the facts I have listed…
That is the standard narrative peddled by those who insist, for whatever ideological reason they prefer, that things are better for us than they’ve ever been.
Non sequitur.
…the evidence that points to a very different way of life to the ‘nasty, brutish and short’ existence stereotypically ascribed to early humans.
By the atheist Thomas Hobbes - who was indeed correct if we are no more than sparks in the dark.
…to say nothing of the fact that we barely recognise, today, the kinds of subtle non-verbal communicative abilities that our ancestors would likely have employed as a matter of course.
Non-verbal abilities which mysteriously overcame the primitive instincts which still dominate many people today?