Is it necessary to quarantine Aussies on Christmas Island to stop coronavirus?

The WHO has declared the coronavirus a public health emergency of international concern, reinforcing the need for countries around the world to act decisively in the face of this epidemic.
The Australian Government is currently negotiating with the Chinese Government to fly a portion of the 600 Australian citizens trapped in Wuhan back to Australia.
The controversial plan is to quarantine the evacuees on Christmas Island, 2600km off the coast of WA, where they will remain for 14 days.
Many have condemned this measure as a harsh response — isolating healthy Australians on a tiny remote island, most infamously known as a refugee detention centre, to protect the rest of the Australian population.