Regardless, it's heinous to justify a crime like this. It also leaves an extremely bitter taste to come across a museum in Europe with artifacts stolen during some more blatantly colonial period that they forgot to return.
Look at what ISIS did to the pre-Islamic artefacts present in the territory they controlled.
Look what Saddam Hussein did (even with somewhat good intentions) by trying to "modernize" the remains of the Ishtar Gate for the consumption of the local people, while ignoring pleas from archæologists to let them thoroughly review the sites beforehand.
I, for one, am thankful that I can go to the Louvre and learn about our shared ancient history, rather than these artefacts ending up as a paper weight in some oligarch's office, as would have been bound to happen otherwise.
We went to Iran for our holiday and we went to Persepolis and often enough it was mentioned that certain items (small and very big) are not here but you can see them in London or Paris ...
It is quite irritating to be honest traveling from Europe to Iran and realizing how much actually is at home.
Nonetheless, while i think this is not an easy topic, we europen were who traveled there and realized that this thing is actually worth digging out and saving. Before those stones got taken away slowly and steadily.