If nothing else it wasn't plunder. The Elgin marbles were obtained during a time of peace, not war so are not plunder. The exact legitimacy of the removal could be argued (and was), but it wasn't done in secret, nor by force, and there is no evidence of any objection by the Islamic authorities to the removal of idolatrous statues. Elgin was the British Ambassador to the Ottoman Empire. In any case it is irrelevant to the argument that art should be returned to its place and culture of origin. China does this by a policy of purchase. Benin Bronzes (actual plunder) by politics. The Bayeux tapestry by temporary loan.What makes that an exception?
The issue is whether Columbus should be glorified given his actions. The Elgin marbles are often referred to as the Parthenon marbles so as to not glorify Elgin. Columbus destroyed the art and culture of native Americans taking gold by force*; Elgin sought to preserve the art and culture of ancient Greece.
*As Trump would say 'to the victor go the spoils', I am sure Trump would oppose the return of art gained by plunder.
