lol @ not wanting your lifestyle to be deteriorated making you a classist or elitist. That would describe just about anyone who wouldn't want to split their current food store amongst all those with less food in their community, or anyone that isn't willing to open up their living room to the homeless in their community.
Hardly the same case due to the scale of the situation. And by definition it certainly would fit under the category of classism and elitism.
In addition to the basic behaviors, The Ark was designed as an experiment in self sufficient green living in hopes of finding a permanent solution to the world's issues, funded by a collection of live-in benefactors that enjoyed their personal eden while the scientists did their research.
The survivors of those issues come in search of the solution and accept residence and employment under the original inhabitants and live that way for X number of years, but are kept as "outsiders" by those currently running the Ark, which are either the wealthy or the scientists and you rarely see scientists in politics.
Now what reason could there be to allow the refugees to stay, but not stay within the city limits? Maybe security issues, except we know the refugees are working maintenance jobs and those jobs obviously aren't in container city. Possibly not enough space? Well then we wouldn't have this abandoned airport. So we head to your "not wanting your lifestyle to be deteriorated" as a possible issue.
The world as we know it has ended. The Ark is, for all intents and purposes, the last hope for humanity. If the concern is dwindling resources, where the refugees are living is not an issue, the fact that they are living at all is the issue (A fact that I suspect is part of what plays into the conspiring nature of the story). Keeping them separate is a definitive act of classist behavior.