It may be confusing by the way it is worded.
See if this helps.
The head of the femur belongs in the center of the hip capsule.
Sitting all day the head of the femur will move to the back of the hip capsule.
With the banded distraction the femur is moved to the center of hip capsule. This is where the head of the femur belongs. The head of the femur in the center of the capsule effectively clears the impingement.

With an impingement at the front of your hips you mobilize to the back of the capsule to move the femur from the front of the capsule. As you crawl forward you bias the tissues at the front of your hip capsule.

You use a band to create space and facilitate movement around the joint.
Hooking a band around the hip allows you to pull joint surfaces apart so you can reset the joint into a good position.

You can create a distraction in different directions.
Distract laterally pulls your hip into the side of the capsule.
Distract toward the posterior pulls your hip to the back of the socket.
Anterior distraction pulls the hip forward.

Depending on the situation you can run into the front or the back of the capsule.
You could be seeing an up/down stream compensation of another issue.
The distraction creates space to facilitate movement into a better position.