Christmas Island was sold against the interest of Singapore. But then, what could the residents of the island do when they were still subjects of an Empire, and the colonial masters said so? Under those circumstances, when the people had no control over their destiny, you can’t really blame anyone for selling out the island. Under those circumstances, it is not right to accuse Lim Yew Hock for selling the island, or a traitor to the people of Singapore. The people then were not owners, mostly stateless. One only becomes a traitor to the people if the people own the land that was sold away.
Christmas Island can still be sold without selling it the way it was sold, lock, stock and barrel, to another country. Say the residents of Christmas Island, a tiny little piece of rock, decided that they could build properties and sell them to foreigners. In no time every piece of land will be sold to the rich foreigners and the foreigners became de facto owners of the island.
Another way of selling the island against the interests of its inhabitants is to bring in more foreigners to populate the island in the name of progress. When the foreigners become the majority in the island, they will literally inherit everything in the island from its original inhabitants.
Sure, in the name of economic progress, Christmas Island could be the next cosmopolitan city island in the world, the perfect playground for the rich and famous. What about its poor inhabitants? Squeezed out of the island and lost the island forever, to a bunch of new owners.
Selling out in another form. At the end of the day the island will have new owners, belong to other people forever, no longer own by the islanders.