Deuteronomy 28 is a record of what will happen, not what has happened. Why OP didn't point this out is known only to him, but since he didn't preface his question with the information, there must be a reason. It seems to me there are only three options:
he doesn't know
he doesn't care
he is trying to perpetrate deception
I will give OP the benefit of the doubt and suggest the second option, "he doesn't care". But, I care. So, I'll fill in the stuff that he doesn't care about.
Chapter 28 of Deuteronomy starts:
And it shall come to pass, if thou shalt hearken diligently unto the voice of the LORD thy God, to observe and to do all his commandments which I command thee this day, that the LORD thy God will set thee on high above all nations of the earth:
-- Deuteronomy 28:1
In other words, if Israel behaves differently to the nations they were going in to displace (pssst, they hadn't done it yet), then God will bless them and make them the premier nation on the planet.
As I pointed out in an answer to another question by OP, the nations that Israel were being brought in by God to displace, perpetrated great wickedness upon their women (Deuteronomy 18):
men having sex with their mother and aunts, sisters and daughters;
men having sex with a women during menstruation;
men causing women/daughters to have sex with animals;
men sacrificing their daughters to the gods of the land;
This behaviour made the people of the land a pestilence, and the land spewed them out, i.e. they made the Earth sick.
Deuteronomy 28:2-14 then goes on to detail the blessings that Israel would enjoy if it held to the principles of life God had given to the people. Deuteronomy 28:15-68 is the other side of the coin, and details the curses, three times the number of verses given to the blessings, such was God's concern that they fully understood what would befall them if they were to discard his principles of life. So, instead of being set "on high above all nations of the earth" (Deuteronomy 28:1), they would become "an astonishment, a proverb, and a byword, among all nations" (Deuteronomy 28:37).
The LORD shall send upon thee cursing, vexation, and rebuke, in all that thou settest thine hand unto for to do, until thou be destroyed, and until thou perish quickly; because of the wickedness of thy doings, whereby thou hast forsaken me.
-- Deuteronomy 28:20
If Israel were to become a pestilence on the Earth, like the nations they were to displace, like the people on the Earth prior to the Flood, like the people of Sodom and Gomorrah, why should they not expect to be destroyed? God, being the loving deity that he is, was making it known to his people that they had a choice in whether or not their destruction would be necessary. As Adam and Eve were put in control of their continued existence in Eden, so too would Israel be put in control of their continued existence in Canaan.
Now, as to God rejoicing/being pleased/delighting in watching rape, no such thing is being said in the text. It says:
And it shall come to pass, that as the LORD rejoiced over you to do you good, and to multiply you; so the LORD will rejoice over you to destroy you, and to bring you to nought; and ye shall be plucked from off the land whither thou goest to possess it.
-- Deuteronomy 28:63
God will delight in wickedness being removed from the Earth, in the same way modern moralists delight in pedophiles, especially priests or ministers of religion, being cut off (sic) from among the people (incarcerated, that is). No one delights in the knowledge that the wicked should prosper, except the wicked. And portraying God's delight in the removal of wickedness as delight in watching rape, is an argument in support of wickedness.
The writer to the Hebrews says this about the word of God:
For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.
-- Hebrews 4:12
One can come to the text of the Bible with the same Spirit that moved its authors to write, or with a spirit that is opposed to such. The things a person takes time to publish in regard to what they have discovered in the Bible, is the evidence of which Spirit/spirit is moving their hearts and minds.