Jedi do not fight for peace. That's only a slogan, and is as misleading as slogans always are. Jedi fight for civilization, because only civilization creates peace. We fight for justice because justice is the fundamental bedrock of civilization: an unjust civilization is built upon sand. It does not long survive a storm.
...you must understand that not even the Jedi know all there is to be known about the Force; no mortal mind can. We speak of the as someone ignorant of gravity might say it is the will of a river to flow to the ocean; it is a metaphor that describes our ignorance. The simple truth - if any truth is ever simple - is that we do not truly know what the will of the Force may be. We can know. It is so far beyond our limited understanding that we can only surrender to its mystery.
Only on a planet such as Coruscant, with no forests left, no mountains unleveled, no streams left to run their own course, could the Force have become so clouded.
To those who still deludedly think they prefer Star Wars over Ghostbusters, all I need to do is ask you is this: You don't really want to be a Jedi, do you? In a greige cowl, getting off with your sister, without a single gag across three films? I think if you thought about it a little while longer, you'd realize that you'd far rather be a Ghostbuster: a nerd in New York with an unlicensed nuclear accelerator on your back, and a one-in-four chance of being Bill Murray.