People don't just fall apart and give up on every shred of morality just because they're in a rough situation, despite what NuBSG tells us.
BSG said nothing of the sort.
As for Voyager, I'm always surprised when people express disappointment over the lack of Maquis-tension throughout the series. Did these people even watch the first episode? Realistic or no, Voyager ended up being very true to that speech in Caretaker.
My problems with VOY begin with "Caretaker."
Simply put, I don't recognize Janeway as having the legitimate right to press the Maquis into Starfleet service.
About 1/3rd of Voyager's crew died during transport to the Delta Quadrant. The Maquis who came aboard after sacrificing their vessel to save Voyager and the Ocampa took up the dead third's positions.
In other words, the Starfleeters needed the Maquis to serve as crewmembers to get home, and the Maquis needed the Starfleeters to get home.
As a result, neither side should have been given power over the other. Voyager should have been run as a joint Starfleet-Maquis vessel, with an ad hoc command structure negotiated by Janeway & Tuvok on one side and Chakotay and B'Elanna on the other. The chain of command on Voyager should have been completely different, should have borne no resemblance to anything we'd seen on Star Trek before. Chakotay should have been a much more powerful figure -- a co-captain, or at least a sort of "Vice President" figure with veto power.
Janeway should never have been able to just rely on Starfleet ranks for authority, because Chakotay should always have been willing to say, "We're not part of Starfleet, and if you try to run roughshod over us, the Maquis will leave and then neither of us are getting home. Treat us like equals or we all lose."
And frankly, that would have been a lot closer to Federation values and ideals than forcing a group of people who had legitimate grievances against the Federation government to serve in its military or be stranded on the other side of the galaxy. What VOY depicted was not the triumph of Federation values -- it was the triumph of ethnocentrism and conscription over egalitarianism.

That was mostly a setup for the following point, after all.