I went searching for an attribution for that quote and found nothing, but did turn up this Guardian article which has this quote:

MacGregor has been fascinated to see at close quarters the Chinese beginning to open up to the world. It had initially been hard, he suggested, even to describe the concept of the British Museum to the Chinese, its role as a storehouse of global memory. 'It is,' he told me, 'an alien concept for the Chinese to have a museum that houses the whole world. Their museums only have Chinese objects in them..."

HOW DID THE BRITISH MUSEUM GET THOSE ARTIFACTS MACGREGOR. HOW