The official opprobrium heaped on Palestinian militants, for example, is primarily a matter of condemning the enemies of an allied state; their use of terrorist tactics is secondary to whether or not they are labeled this.
It's that "entirely" that I don't buy.
I must say that whatever reservations I had about the Walt-Mearsheimer book (and I largely share Ross's assessment), Walt's counter-factual post on Gaza has generated a lot of great blog debate. It has helped out the deeper debate we need to have. As has the entire Gaza bombardment.