I have to agree that this is absolutely absurd. It would sure seem that a park ranger isn't 'trained' to fight or defend against the Mexican cartel. Perhaps they will be quickly trained, or will simply be 'spotters' and relay info to the border patrol agents??
That kinda depends. USFS Forest Rangers up in here are a different thing than a Park Ranger, though technically the same to the eye, except one is packing.
A park ranger is something like a camp manager.
A Forest Ranger is a full on sworn LEO, and you don't mess with them. They are out in the middle of nowhere and are very good at taking care of themselves. Just like State Fish and Game wardens, They respond to anything a sheriff or Highway Patrol would, and they all back each other up.
Though I do not know how much good a Forest ranger is going to be in the desert.