I recently read a fascinating book called "Miles from Nowhere" which described life in the least populated counties in the U.S. One recurring theme is that counties with almost no one living in them are subject to being taken over by groups with their own agenda. For example, a county with only 150 people in it might be the target of a group of libertarians. 800 libertarians may agree to move there to set up a libertarian government. The point the book made was that virtually uninhabited is very different than uninhabited, and that there are still people there who have wishes, dreams and rights of their own.
So what you are describing is actually an act of force. Overtaking Nauru for your own purposes is a unilateral destruction of someone's home. Imagine for some odd reason the entire population of China decided to buy out and relocate to your city and turn it into a Chinese culture and economy. You may have nothing against the Chinese or Chinese culture, but you may wish to simply keep your home city as is.
Democracy is often thought of as peaceful, but it can often be a vehicle for the majority to disregard the legitimate needs of the minority.