Okay, if you say so.

In that case, the prospects for a theory of morality are rather hopeless, if we have to wait for "nature" to deliver the verdict. (We'll possibly be dead by then.) — baker

No it isn't. Natural selection shows us that morality is a social construction.

No, stay and fight!

Natural selection shows us that morality is a social construction. — Harry Hindu

Could you sketch out how it does that?
I can't think of an unequivocal way to interpret "morality is a social construction".

To the OP, it seems to me that losers are more likely to adopt extremely relativistic if not opportunistic morals, in order to justify their losing. Trump for instance is both a loser and an extreme case of moral relativism.

There's nothing to fight about. I responded to the OP and you disagree with some of my suggestions. Okay. There are others you don't, so look into those. You stay away from that "car without an engine" and I'll ride this Pegasus without wings koan.

Only expressions of morality (codes of conduct, or normative conventions) are "social constructs". Humans are eusocial animals and instincts for (a) reciprocal harm avoidance, (b) burden-sharing and (c) discouraging free-loading / burden-shifting – my terminology – constitute human eusociality. Studies in early human development demonstrate fairness (b, c) and inclusivity (a, b) preferences (i.e. empathy instincts) are expressed prior to 'normative' socialization ...

https://blogs.scientificamerican.com/observations/do-kids-have-a-fundamental-sense-of-fairness/

Our manifest 'moralities' are then socially constructed, with all the cultural-ecological variation (drift) this implies, extending as well as supervening on these empathy instincts. Studies in primates, cetaceans, elephants and other eusocial mammal species have also shown similar degrees of empathy as well. Consider ...

https://yoursay.plos.org/2012/03/27/should-chimpanzees-have-moral-standing-an-interview-with-frans-de-waal/