According to the UN world Map this whole arcipelago is called "Chagos Archipelago" and it belongs to Mauritius (https://www.un.org/geospatial/content/map-world). This would reflect the international Law as decided in the advisory opinion of the ICJ (https://www.icj-cij.org/en/case/169) and the resolutions of the UN that followed. But this does not reflect the position on the ground, as it is administered by the UK.
Shouldn't OSM follow international law (as it does for Crimea etc.) and change the name? Thanks for a clarification :)