No, it would be the groups willing to use force to gain power. Force works. It might not be nice, but that's how it is.
There are situations in which the only way to peace is to force it on people, Pax Romana style. If <insert group here> is willing to use guns and bombs to kill any who openly oppose them and suppress opposition through fear, then they will come to power if there isn't an effective opposition to them, and that requires an armed force. If <insert group here> is eager to do some mass slaughter "cleansing" for ethnic, religious and/or political reasons, stopping them in the short term requires greatly superior force, enough to prevent them doing it. "Kill those people and we kill you" is ugly, but in some situations it's the only thing that works. Long term requires deeper changes, but that's not going to bring the dead back to life.
What you're proposing is an international military spanning dozens of countries without military training in those countries, which can't work unless there is far more unification between all those countries than currently exists. The most workable solution at the moment is, as it always has been, alliances.
I'm trying to find a quote and failing. It's something someone said to someone else after hearing a third person propose disarmament, something along the lines of him being a good man, but until all men are like him we must keep our swords sharp.
But it did work!
