However, the setting of Fallout is not an ideal utopia, where philosophy comes first. It is a harsh and unforgiving environment, filled with hundreds if not thousands of people who want nothing more than the gruesome demise of every other living thing in sight. Because of this some might beleive that slavery is acceptable when it provides security and stability. This is where the Legion clearly outshines the NCR.
While I personally despise the Legion and everything they stand for, I can understand why some might want to join their ranks. Personally I don't think a massive military based society ruled by a sociopathic dictator is the long term solution to the Wasteland's problems. I also have doubts that Cesar, as old and physically frail as her is, would live to see the day when he has even half of the former US under his control, let alone enough of an empire to justify the coutnless misery and enslavement to thousands along the road.
In closing I think I'll quote Ben Franklin: "They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety."
Just my opinion though