But they are forced to be soldiers, you don't have a choice. He brings peace, but ruins everyones lives to do so.
Caesar entered The Strip as though it was his Triumph. The Legion pushed the NCR out of New Vegas entirely, driving them back to the Mojave Outpost. The Legion occupied all major locations, enslaving much of the population and peacefully lording over the rest. Under the Legion's banner, civilization - unforgiving as it was - finally came to the Mojave Wasteland.
So he gets to peacefully control a small amount of people. You may be confusing stability with peace, because to me it seems pretty obvious that they are stable, as long as Caesar lives.
Way to misdirect.
How about we try it another way?
Caesar entered The Strip as though it was his Triumph. The Legion pushed the NCR out of New Vegas entirely, driving them back to the Mojave Outpost. The Legion occupied all major locations, enslaving much of the population and peacefully lording over the rest. Under the Legion's banner, civilization - unforgiving as it was - finally came to the Mojave Wasteland. Oh and how about that Primm ending where they aren't killed or enslaved?
I'll tell you what they became; Citizens.
Legion has citizens too, we just don't see anything but warcamps in New Vegas as it's not their territory.