It's fun to say this, but at least BM is really able to do their main job and preserve the artifacts.
There's dozens of cases where the original sites have been looted or destroyed by the origin country's own leaders.
Storing the artifacts outside of the influence of an area's internal issues is actually really wise. The BM's real wrongdoing is not paying anything for the artifacts they've took. I argue they've done enough good to offset that a little. They're bad but not the worst.