Please. The context of her speech is the Horde and them stealing the Bell. How do you think she knew it's the Horde that was helped by someone from Dalaran? There was no one else trying to enter Darnassus to get the Divine Bell. There's no one else who even knew about it. Even that aside, there could be a member of every faction on Azeroth trying to enter Darnassus. That'd make them enemies of Darnassus and Jaina would still be breaking neutrality by aiding Darnassus against them through hostile actions. And Kirin Tor has no authority whatsoever over those other factions to prevent them from doing anything.