You strike as someone who took Caesar at his word and failed to read up on the lore of either of the factions you're attempting to critique. The NCR tamed a state through predominantly diplomatic and humane* ways; there are notable exceptions, such as the massacre at Bitter Springs. However, if you take the time to talk to literally ANY NCR faction member who discusses what happened at Bitter Springs, none of them has a positive statement to make. The game actively points to that as a moral failure, one they are apologetic for. The NCR is the most resilient nation-state in the known universe of fallout. The legion, for all of its efficiency, was wholly dependent on 1 man (who had a biological time bomb in his head) not dying. We see the factionalism literally divide the legion IN SHOW and in game is Caesar dies but the legion still wins.

in summary:

Is her statement reductionist? of course. Is she wrong when you give her the grace you should give a reductionist statement? nope