I'm guessing it's because both Calacanis and Arrington are important players in the Valley startup scene, and it's good to know what they are like to do business with. Personally, as someone living in Europe, I agree with you, this doesn't seem at all interesting/useful to me, but I can understand how this would be of interest to many HN participants.
It's also a useful case study in how co-founders can try and screw each other over, and how important it is for them to be on the same side. That's a pretty general lesson.
