Open Street Map has much more detail, and shows the harbour at Georgetown: https://osm.org/go/PzLP7syAF- as well as what I think might be an oil/fuel terminal for the power station further north.
There are also pipelines from a fuel storage depot in Georgetown to the RAF base (south), which has pipelines to the coast, so there must be others too.
Look closer at that harbour. Especially its scale, and facilities. There's nothing resembling a spot to tie up (say) a 500' freighter. Nor a breakwater - if a storm hit the west side of the island, then everything afloat would have to be hauled out of the water, or flee.
(Yes, obviously my original comment should have been more specific.)
For military facilities, on a military budget, there's all sorts of "wait 'till the weather and tides are right, then transfer cargo ashore via helicopters and small boats" stuff that you can do. At commercial scale, the extra costs are poison.
Open Street Map has much more detail, and shows the harbour at Georgetown: https://osm.org/go/PzLP7syAF- as well as what I think might be an oil/fuel terminal for the power station further north.
There are also pipelines from a fuel storage depot in Georgetown to the RAF base (south), which has pipelines to the coast, so there must be others too.