Those umwanted consequences you want to put on the back burner could very well show up at your doorstep or in your bedroom while your sleeping.
You don't fight crime with crime.
I understand. However, several years back I was living in southamerica and I saw crime rise fast. It should have been stopped when it was possible. Now it's too late. I don't know if you have ever been attacked by any of these vicious criminals, but once it happens (and I certainly hope it does not happen to you), you just understand that any measure has to be massive.
Sure, you can always put them in jail and let them walk in a few days due to the Codigo Procesal Penal.
Furthermore, I understand the shooting was coming from both sides (maybe not true), so that would rule that out as a crime.