What has happened in Deuteronomy 28 is God's own doing. Not simply because he removed his protection, but the horrors that take place are God's judgment. Not saying you, but there are some here who will outright reject this truth. He has a track record of using evil nations and evil people and evil creatures to accomplish his will, especially in judgment. This is how we know he is sovereign.
20 “The Lord will send on you curses, confusion, and frustration in all that you undertake to do, until you are destroyed and perish quickly on account of the evil of your deeds, because you have forsaken me.
21 The Lord will make the pestilence stick to you until he has consumed you off the land that you are entering to take possession of it.
22 The Lord will strike you with wasting disease and with fever, inflammation and fiery heat, and with drought and with blight and with mildew. They shall pursue you until you perish.
24 The Lord will make the rain of your land powder. From heaven dust shall come down on you until you are destroyed.
25 “The Lord will cause you to be defeated before your enemies. You shall go out one way against them and flee seven ways before them. And you shall be a horror to all the kingdoms of the earth.
27 The Lord will strike you with the boils of Egypt, and with tumors and scabs and itch, of which you cannot be healed.
28 The Lord will strike you with madness and blindness and confusion of mind
35 The Lord will strike you on the knees and on the legs with grievous boils of which you cannot be healed, from the sole of your foot to the crown of your head.
36 “The Lord will bring you and your king whom you set over you to a nation that neither you nor your fathers have known. And there you shall serve other gods of wood and stone.
37 And you shall become a horror, a proverb, and a byword among all the peoples where the Lord will lead you away.
48 therefore you shall serve your enemies whom the Lord will send against you, in hunger and thirst, in nakedness, and lacking everything. And he will put a yoke of iron on your neck until he has destroyed you.
49 The Lord will bring a nation against you from far away, from the end of the earth, swooping down like the eagle, a nation whose language you do not understand