Suppose that you run a major art gallery, which owns an iconic piece by Rembrandt.    There isn't a jurisdiction on the planet which allows you to claim copyright on the picture itself, but you can control the ability of others to create replicas of it.   If the only authorised, good-quality reproductions are the gallery's own, then the gallery is entitled to sue an unauthorised, good-quality reproduction, on suspicion of its being an ilegal copy of the gallery's reproduction.    The gallery has the responsibility for the upkeep, insurance and (perhaps) repair of the original artwork, so is entitled to protect the income which that artwork generates.

I suspect that that is all that the Egyptians are trying to do here.   I also suspect that that is nothing new.    There has been a high-profile exhibition of artefacts from the tomb of Tutankhamun in London lately.   This announcement may have been a shot across the bows of anyone seeking to copy the official merchandise.   To that extent, it seems entirely reasonable to me.