Should the people who use an .IO domain name anticipate any input about how they do business from former residents of the Chagos Archipelago, or alternatively the British military?
I'm pretty sure that national governments do have some level of control over national TLDs. Some of them don't allow privately-owned sites under their TLDs at all.
The British Indian Oceans territory was never a country, and never had any citizens. There was no indigenous people. None of the former or current residents (hired workers) ever owned any of the land.