The stinking Greek Commies ( bet ya didn't know this ! ) tried to get them back decades ago. It was NOT because of " cultural heritage "; it was to thumb their nose at " democarcy " and the Brits.
Greece isn't nearly as " open " a society, as you imagine it to be.
The British Museum owns those marbles fair & square ! They're beautiful, but not in great condition, due to the fact that the Greeks had once used them for target practice and building material.
You aren't making much sense. Facts and history matter; learn some and stop being such an emotional poster.