> Why not just accept the situation as part of the ebb and flow of history?
Why would you? By calling it the 'ebb and flow of history' you seem to imply that the things we do to each other is beyond the control of humans.
But of course we're fully in control of what we do, so the question is rather: if we have the possibility to do good, and it comes at virtually no cost to us, then why not do good?
In my opinion it’s still more driven by nationalistic agendas than the ethical imperative and as others have said there are good reasons to leave the artifacts where they are. I’ve only ever seen people make heated demands based on past grievances. A lot of this stuff happened a long time ago now, anyone influential has died, it really is time to at least take the heat of these conversations.