Be the change you want in this world. Why don't you go to El Salvador yourself and "fix" these criminals. I can't wait to see the results.
Is civil war forever really the best policy? At some point it makes sense to realize war is costly, both in terms of lives and the economy. When is it time to just try to make the best peace you can?
Is acquiescing to violent murderers and criminals?
If it stops them from murdering as much, it might be? The options seem to be they murder indiscriminately because they pretty much control the government or they murder less indiscriminately because they came to an agreement on when it's ok to murder with the government. I think option 2 is better, but different normative ethical philosophies certainly disagree.