Why did a “loving” God permit the evil of the Holocaust?
God allows evil to exist because we chose it, self-righteousness and narcissism, over His paradise; also, our entire creation is the resultant of a war initiated in the Spiritual Realm and this Earth is a temporary repository for that war as God is demonstrating to the faithful angelic creation (that He adores beyond human comprehension) the ramifications, the horror, of disobedience and rejection of His law and His love. Truth be told, human beings think far too much of themselves and live and act as if God owes us something as though we’re entitled.
The thousands-of-years of Satan’s limited dominion upon the Earth will ultimately act as a bulwark against future rebellion in the Kingdom of God where free will remains extant out of necessity. Human kind has been given the opportunity by grace to ally with God in this war between good and evil by following and serving Jesus Christ as Lord; you are free to choose victory in Jesus Christ and live eternally; you are free to choose defeat in Satan and die the “second death” in Hell as God’s enemy. You are free to choose your eternal destiny; this is war, you’re a warrior regardless of your station in life; therefore, choose wisely!