i was under the impression it was a case of them leeching too many resources not a disagreement on searching for alternative accomodation. from the story i've read the ark was a sustainable community "project" designed for 5000 people. it's now "sustaining" 40,000 against an unknown apocolypse event. the reseource reclamation was never designed fior such a large volume of people. the refugees may be completely oblivious to such things though and simply think the have's are keeping the have-not's down.
from what i've seen neither side really see's the conflict from the others eye's which puts players in the rare position of knowing both sides of the story firsthand if they play both sides.
DLC however shouldn't be shackled by story. expansions YES, DLC no. i still think the mechanics are perfect for a 16 player survival against the zombie horde gametype. especially if those who fall get switched to zombie on respawn.
Yes, you have that part right, but the conflict stems from an argument about "what do we do next?"
The founders would like to put all resources and manpower into keeping the Ark running for as long as possible. The Resistance would like to use some of the resources to build a vessel of some sort and try to find a more sustainable lifestyle, because the Ark is eventually going to break down. If the Resistance have their way, the Ark will fall apart even sooner, and the expedition to find land might turn out to be fruitless. On the other hand, the Ark is eventually going to fail anyway, and finding land is the only long-term choice available.
The difference in living style only stands to make the resistance more fed up with the situation. "Of course the founders just want to stay, they're still comfortable."
Now, what I'm about to say next is purely guesswork on my part, but it seems to me that the founders may have a lot to gain from the war. The security force is mostly made up of refugees as well, paid with water rations to "keep the peace". Having refugees kill refugees will decrease the population dramatically, which would make life easier for the well-to-do founders. I wouldn't be surprised to find out that some of the leaders of the founders intentionally inflamed the Resistance to start the war.