Question: If Malchut is the desire to receive pleasure, how can she gather all the souls under her wing?
Answer: Malchut is the will to enjoy. It used to include all the desire to receive created by the Creator. Later, it was broken in order to give this desire a capacity to know itself and the Creator, and based on that knowledge, to perform autonomous actions. In other words, it broke into multiple, fragmented parts that feel hateful and disconnected.
Malchut is the point where all the broken parts used to reside. Now, by their own free will and effort, these fragmented parts are gradually coming into oneness in the same Malchut, in their root.
It could be described in other words: The created being, in its experience and perception, is divided into multiple parts which seem alien to one another. These parts must keep uniting together until they feel bonded. An example of such oneness is the upper one, Zeir Anpin, which manifests according to their effort.
From the 1st part of the Daily Kabbalah Lesson 2/6/2011, Writings of Rabash