Why?
"...thieves, murderers, and other malefactors are God's instruments, which he uses to execute what he hath decreed in himself' (CaIv. Inst., b. 1, c. 17, sec. 5.)Even Calvin admitted it to be a horrible concept and claimed that it didn't make God the author of sin but in spite of his protestations to the contrary, he said,
"The devil and wicked men are so held in on every side with the hand of God, that they cannot conceive, or contrive, or execute any mischief, any farther than God himself doth not permit only, but command. Nor are they only held in fetters, but compelled also, as with a bridle, to perform obedience to those commands." (Calv. Inst., b. 1, c. 17, sec. 11.)
"God of his own good pleasure ordains that many should be born, who are from the womb devoted to inevitable damnation. If any man pretend that God's foreknowledge lays them under no necessity of being dammed, but rather that he decreed their damnation because he foreknew their wickedness, I grant that God's foreknowledge alone lays no necessity on the creature; but eternal life and death depend on the will rather than the foreknowledge of God. If God only foreknew all things that relate to all men, and did not decree and ordain them also, then might be inquired whether or no his foreknowledge necessitates the thing foreknown. But seeing he therefore foreknows all things that will come to pass, because he has decreed they shall come to pass, it is vain to contend about foreknowledge, since it so plain all things come to pass by God's positive decree."
--Calv. Inst., b. 3, c. 23, sec. 6.)
"I confess it is a horrible decree; yet no one can deny but God foreknew Adam's fall, and therefore foreknew it, because he had ordained it so by his own decree." (Calv. Inst., b. 3, c. 23, sec. 7.)Others attempted by rather Jesuitical reasoning to claim that, although God causes people to commit the action that is sinful, he himself is not the author of sin because he is under no law and, therefore, cannot do anything that is sinful. Fortunately, God's grace surpasses man's weird views of him and can enable someone to build a prison ministry like CC's.