Why do former colonialists continue to keep looted artifacts in their museums?

[JeromeTash]

Once in a while, I keep coming across articles or documentaries about the historical artifacts that were looted by colonialists from their colonies and are now kept hostage in European museums despite pleas to have them returned to the countries of Origin.

Why is it so hard for the former colonialists to do the right thing and return what was looted to the rightful owners?
What is the point of claiming that the former colonies are now "independent" yet part of their past histories and cultures are locked up in museums in Europe?

Image sources and further reading:
1. https://www.dw.com/en/the-uphill-battle-to-repatriate-indias-stolen-treasures/a-57593591
2. https://www.nytimes.com/2020/10/16/learning/should-museums-return-looted-artifacts-to-their-countries-of-origin.html
3. https://edition.cnn.com/style/article/return-stolen-treasures-geoffrey-robertson/index.html