Double Doors

You’re walking into or out of a set of double doors in some building. You notice through the glass another individual approaching the same set of DOUBLE doors. They begin to slow their pace. You reach for the door. They stop. You open your side of the door, walk through and they then walk through the door that you opened.

Why?! These are double doors! Doors made of two standard size regular doors that can accommodate one individual each. Surely they are capable of pulling there side of the door open themselves? Or perhaps the concept is too complicated for them.