That's because we as a society tolerate it. This behavior is no different from jewelers taking gold teeth in Nazi Germany or art dealers pretending that they did not know where the paintings came from.

As a marginally civilized society, we have dealt with it - it involved international tribunals, nazi hunters, quick trials and bullets between the eyes after which gold dealers as if by magic were not taking gold teeth and art dealers were not taking magically re-appearing artworks.