The whole thing is quite unusual. The UK desperately trying to give up territory and the US not wanting it to happen because they have a shared military base there (which the prior UK/Mauritius deal agrees to lease back anyway).

The most bizarre part of it is that Mauritius doesn’t seem to really want it back. It is, after all, not worth much (especially if the UK/US are retaining their base for 99 years), and is over 1500km away.

The only angle of it that makes sense why the US may be pissed off about it is that China could start trying to influence or pay off Mauritius, to spy, etc. to the detriment of the US/UK. Which tbf is very much something China would do.

But why does the UK want rid of this territory so bad?