Nature would veto gay " mating " - but without political malice

  Just a friendly philosophical question : since when did gay marriage become a self-evident legal right ? Why was it not  recognized in VERY GAY ancient Greece ?
   On the so called intellectual Left there has been much intellectual dishonesty on gay marriage- a product of rather fatuous identity politics.
         The " prejudice " against gay " mating " does have some rather high powered Darwinian support.Nature would veto it-  but without political malice.