I voted because BJ is MMA royalty, however, I think it probabley had something to do with all of the above.
I think it's a bit unfair on Edgar tbh. He has to beat BJ Penn twice in order to be the champ effectively. I think the better idea would have been to put Edgar in against Gray Maynard or Kenny Florian, then after BJ fights someone else in the meantime then gets his shot at a later date. That said I can definitely see why they are giving Penn the immediate rematch. He's a superstar for starters and he looked like **** in the fight, so obviously they want to see Penn at his best.