Did the Romans have parade armour?

[Urselius]

Nice trick. Burden of proof, I would say.
You say: "Such and such societies behave so-and-so and/or in such-and-such patterns".
Proove it, if you want others to believe it.

Well, yes. Then one first would have to find out, how homogenous such societies were, and where and how they were following certain behaviours. Very complicated for Antiquity.

Well, from an evolutionary perspective this is not correct. And from a culturally perspective either. Or are those, who do behave differently no humans?

Comparative anthropology is not as amenable to formal proofs as physics or mathematics are. Beyond producing parallels from different societies, and I have done so for societies covering 5 thousand years of history, there is no way of proving or disproving my hypothesis. If, on the other hand you can come up with a society which produced nothing but entirely practical artifacts then you will have dented my hypothesis.

By using the word 'human' the implication was, as you are no doubt aware, "Modern Human." However, the Neanderthals incised ornament into objects, used pigments (presumably to decorate themselves), and manufactured personal ornaments from animal teeth and mollusc shells, so perhaps they could be included. Homo ergaster (working from memory here, but certainly an extinct hominin) is known to have produced hand axes far too large to have been of practical use, and therefore probably of symbolic importance. We have half a million years or so of human effort which has gone into producing non-practical articles.