I only realize now how similar this is to your Jings post in the RPG section.. You suggested that if someone runs at another person they get a boost, and here it is again..
Jings are present in the martial arts in the same way as they are present in the elements, so does that explain it?
Fire is positive jing, positive jing is offensive, Northern shaolin is a offensive element simply for an example.
Honestly, tai chi may just be a better element for air then baguazhang, but tai chi is the waterbending martial art.