I think I understand it pretty well. I'm just basing my take on it off of everything that I've read and seen. What you've described is not mutually exclusive of what I did; in fact it's all part-and-parcel of the same conflict. Yes, the future of the Ark seems to be a top priority for both sides, but the struggle itself is based on each side being more interested in their own future than the others, naturally. If there was no inequity, they'd be able to work together for the common goal of sustaining the Ark until a viable permanent solution is discovered.
Sustaining the Ark is not possible no matter what happens. Even if all the people were given exactly equal rations, you would still have a big debate over what to do.
The one side wants to funnel resources into making a vessel and then going to find land.
The other side would rather play it safe and keep the Ark running for as long as possible, without wasting any resources on a gamble.
But the problem is, the ones who want to stay are the ones with the power, so the Resistance has decided to take what they have to in order to get off the Ark.
P.S. By your argument, Republicans and Democrats shouldn't have any problems getting along, since they both have the goal of Improving the quality of life in America. Before you say that there is social inequality there as well, I know rich democrats and poor republicans. Even in socialist nations, you still have disagreements about what to do in response to a crisis.