There was some fallout regarding Bungie's decision not to open ODST's Firefight mode to matchmaking, but that may be one of the worst Goddamned ideas ever conceived, rivaling even Chocolate Covered Foreskins. The parallels here are instructive. Firefight in the absence of camaraderie would be masturbatory bot-grinding. Playing against your average Halo player is bad enough; playing with them may be the only thing less appealing.
It still upsets me because it is not often that I can get a group together to play Firefight but that is never to say that I do not fully understand the decision.