The jail department is criminal department, prison, where citizens are put into jail and given trouble. So if the prisoner says: "Why the American government has created this prison department?" is that valid question? The American government may create prison departments, but why you are interested there? Why you are going there? The real position is: because you are criminal, therefore government has to create such department.
So this material energy is created by Kṛṣṇa because there are some living entities who are not to satisfy Kṛṣṇa but satisfy their senses. For them, it is there, "All right. Your field of activities, here." So it is not Kṛṣṇa's desire. It is fulfill your desire. Because in the spiritual world, Kṛṣṇa is supreme, but if you cannot tolerate Kṛṣṇa's sup . . . even here there are so many: "Why there should be God? I am God. I am God." Are you God?
But you have got this mean mentality that "I am God." You cannot qualify yourself. You do not know what is God, what is the meaning of God. You are claiming "God." Because you do not want to serve God, that is your mentality. So for these last, lowest class of men, there is external energy.