I think you are being deliberately obtuse here. Or maybe you are just dumb? Most societies have no concept of trading based on private knowledge and certainly no taboo against that activity. Hence, there is no universality. Your poor attempts at coming up with counterexamples proves my point.
> Most societies have no concept of trading based on private knowledge and certainly no taboo against that activity
Yes, obviously. That is my point.
But if you insert the word "unlawful" the statement becomes true, vaccously (in the formal meaning of that word) most of the time.