"The goal is peace. if revealing details will not help the goal than why do it?" That's exacty the philosophy of all non-democratic rulers: "I know the goal, I know the best way to get the goal, so I won't let the public intervene, I know better then them". History proves that most of the time, the public knows better than every single ruler. That's why democratic countries are usually more successful than non-democratic ones. You can read about it in, for example, the book: "The Wisdom of Crowds".
Hiding the details from the public goes against the idea of democracy and prevents us from enjoying the wisdom of the crowd.
"The goal is peace" - yes, but who says the government knows better than the public what the best way to achieve peace is?