Check over the last several forum pages, and you'll see several threads about the joys of the diplomatic AI rules. At the moment, they're probably the weakest thing in the game, with plenty of loop holes that translate into contradictory behavior on the part of your AI opponents, sudden shifts in attitude, mass declarations of war, etc.
For example, I had a fellow kingdom AI like me less because I declared war on an empire AI it was also at war with: but the kingdom AI hated war. So that made a lot of sense.
Brad's written about dealing with this at some point, but who knows when that will be? For the moment, I completely ignore the screen. It's not worth the hassles. If I spent more time on it, I'd probably put away the game until a patch improved it.