What justifies the use of force?

Blackflag: Having to many people in the army simply because they are capable, is net harmful.
Having an army at all is net harmful. Regardless this is what's happening, and any discussion that ignores the reality of how an army will inevitably be composed is pointless.

If you have to "think" about whether an army is killing people, then the war is probably not justified.
Oh right. So you don't even think before going to war. You just go to war.

The majority of wars were fought for greed and power, not the civilian.
Power over what? Greed for what? That's a totally meaningless statement.

Given todays technology, and extreme size of NATO's millitary, war can be started and ended in a day, with minimal casualties.
Oh yeah. Like when you guys went to Afghanistan. Great to see that war ending in one day.

The Green Party is researching non-lethal weaponry. That may be the future.
That's stupid. Weaponry by definition is used in combat. The problem is war, and non-lethal weapons don't solve that.

Neither side was killing each other's citizens, therefore, peace was justfully undertaken.
But there was provocation, and one could definitely argue the intention.

Retaliation to a nuke would be unjust as it would kill civilians.
Say you're about to order an attack on a country that has conscription. How would you avoid killing unwilling soldiers?

The whole premise is faulty because I never claimed the basis of evidence on "intention".
Yes you did. Here's the quote:
"Provocation and intention to kill citizens justifies the use of armed force against another army or group"

War is also progressional. WW2 and Iraq needed to happen.
Why?

Blackflag: The majority of wars were fought for greed and power, not the civilian.
All wars have been fought over morality. Someone asserts a right, the opposing side disagrees.

Given todays technology, and extreme size of NATO's millitary, war can be started and ended in a day, with minimal casualties.
That's the theory behind police forces, prevent crime by overmatching criminals by a large margin. What about those who aren't able to overpower criminals easily? What about those situations where a pitched battle or insurgent warfare is needed to fight criminals?