Answer: That is how the upper Light is revealed. Keter is the characteristic of absolute bestowal. Malchut is the characteristic of absolute reception.
The characteristic of Malchut is created from the characteristic of Keter. Since the characteristic of Keter wants to bestow and give everything, its characteristics of bestowal pass from above to below through all kinds of emanations until they give birth to a desire to receive, and therefore, Malchut wants to receive everything that Keter wants to bestow and give. Everything that Keter wants to give is expressed, revealed, and implemented in the eight Sefirot between Keter and Malchut.
The Sefirot of Hochma, Bina, Hesed, Gevura, Tifferet, Netzah, Hod, and Yesod are characteristics that connect the Keter with the Malchut.
Since they receive influence from the characteristic of Keter that descends by way of all these Sefirot, the characteristic of Malchut begins to feel its existence and the desire of Keter to bestow and give to it. As a result of this, a state called shame is discovered in Malchut.
Feeling the difference and gap between the one who bestows and the receiver is so great that Malchut stops receiving from Keter. This state is called a Tzimtzum (Restriction).
This is a state that is even discovered in people who have developed normally in our world.
From the Kabbalah Lesson in Russian 3/5/17