It is clear from this statement, as it has been all along to anyone who bothered to get the facts behind the rhetoric, that these officers were not prosecuted "for doing their jobs," but rather for using excessive force by attempting to butt-stroke a person who was the subject of a routine traffic stop (at which time they had no idea that he had a load of weed in his vehicle), firing at him when he tried to run away, and then violating Border Patrol regulations by not reporting the incident. They both attended a retraining session on these reporting requirements the day before this all took place.
Yes, he was a criminal. Yes, these were duly-appointed officers of the law. Do these two facts add up to giving them blanket permission to do whatever they want to him? I doubt it.