Why the Secrecy? No Shame in Collecting Antiquities, Surely?

The Metropolitan Museum of Art in New York has acquired the gilded lid of a first-century Egyptian coffin [...]  Since 1971, the coffin has been owned by a private collector (whose name is not disclosed on the Met’s website or in the release about the work). It had been sold to the collector by the heirs to the holdings of Habib Tawadrus, an antiquities dealer, and made its way to Europe—with an export license—in 1977.  Alex Greenberger. 'Metropolitan Museum of Art Acquires First-Century Egyptian Coffin', Art News Sept 12th 2017.

As far as I can see, there is no known tomb known of a person of this date and of this name from which this items could have come, which would be odd if it a whole coffin has been above ground from as long ago as half a century ago. The cult of Heryshaf, was centered in ancient Heracleopolis Magna, and an unknown Ptolemaic sanctuary to the god may have existed there too, but seems not to have been excavated.

The export licence no doubt accompanies the object, but why not the collector's name? The latter would have claimed he or she was altruistically 'preserving the object for future generations', so why are they so ashamed to admit who they are? If this is considered to be the common heritage of us all, then why should some of the information about how it came legitimately onto the market be withheld from us all? If the collecting history is indeed kosher, publish all of it. If you get involved in the antiquities trade as a private collector, why should you do so secretly and clandestinely - unless the objects you acquire and your dealings in them do not stand up to proper scrutiny? Collectors, come out of the closet.

Vignette: the coffin is inscribed for Nedjemankh, a priest to the god Heryshef.