There is no point.
Kneepads (especially the kind pictured) are uncomfortable when worn for a long time. They're hot and they cut off circulation. Because some Commands require kneepads be worn, many guys end up pushing them down around their ankles. Other guys might wear one, with the expectation that if they have to pull security for an extended period of time, they can adjust it back up to their knee.
The Iraqi's don't understand any of this, and wear a pad on their ankles because that's what they see the US doing. Then, they wear a second set on their knees, to serve the intended purpose. It is comical.