I always find these conversations strange. The stone was erected by a long dead Greek Pharaoh of an ancient civilization that happened to be located on what is now Egypt. The stone was found in 1798 by the French and taken by the British as a spoil of war and, eventually, found it's way to the British Museum.
Who has claim? The Greeks? It was ruled by a Greek at the time. The Romans who ruled later? The French? The British? The pre-revolution Egyptians? The post coup Egyptians?
Everyone involved is long dead. It's not like WWII looting where the grand child of the former owner wants their property back.
At some point this is all the ancient history of us all.
Hmmm... so, thieves who steal from other thieves may view their actions as less reprehensible than thieves who steal from the original owners?
European colonialism was just an example of a practice that dates back to prehistory, and can even be seen in the behavior of our chimpanzee cousins - 'raiding' is the word for it.
Sorry, I didn't mean to justify it. Just to point out that it wasn't only the British engaging in this behavior. Also I find it a pretty funny historical fact, large part of the British Museum's Egypt collection actually comes from French raids.
