You know, I happen to agree with you. Still, if some kids in the neighborhood were throwing rocks at me and I opened up on them with a gun, I'm pretty sure the cops would arrest me. Why should it be any different if a cop is shooting someone? I'm not saying you couldn't have a rock throwing situation where deadly force could be justified, but is this such a case?
For one thing, the Border Patrol can't call the cops to arrest the rock throwers or make them stop. Self defense is the only option. Again, if it were up to me, I would mine the border with Mexico and put up a warning sign.
I like your attitude. None of us really knows what the hell happened in this case. It warrants investigation. This reminds me of '12 Angry Men'
In most states (though not all), if you're in "imminent danger of great bodily harm," lethal force is justified. When civilians see a bad situation they have the option (and in many circumstances the obligation) to get the hell away before it blows up. Police, on the other hand, are expected to engage. Otherwise cops would run away every time somebody threatens them. Do we want Border Patrol Agents who turn tail every time some kid throws rocks at them? I say no. And if an officer is in imminent danger of great bodily harm, he or she has every right to open fire. So the question is: Were they in imminent danger? If a kid is throwing pebbles from 100 yards away, probly not. If a kids is throwing baseball sized rocks from 20 yards away, definitely yes. Let the investigation begin.