Why Does God Allow the Temple to be Destroyed?

Because once the temple is built before the Great Tribulation starts, the Jews will have already defiled it.

Idolatry in the Temple - Ezekiel 8

Then on September 17,* during the sixth year of King Jehoiachin's captivity, while the leaders of Judah were in my home, the Sovereign LORD took hold of me. 2 I saw a figure that appeared to be a man. From the waist down he looked like a burning flame. From the waist up he looked like gleaming amber. 3 He put out what seemed to be a hand and took me by the hair. Then the Spirit lifted me up into the sky and transported me in a vision of God to Jerusalem. I was taken to the north gate of the inner courtyard of the Temple, where there is a large idol that has made the LORD very angry. 4 Suddenly, the glory of the God of Israel was there, just as I had seen it before in the valley.

5 Then the LORD said to me, "Son of man, look toward the north." So I looked, and there to the north, beside the entrance to the gate of the altar, stood the idol that had made the LORD so angry.

6 "Son of man," he said, "do you see what they are doing? Do you see the great sins the people of Israel are doing to drive me from my Temple? But come, and you will see even greater sins than these!" 7 Then he brought me to the door of the Temple courtyard, where I could see an opening in the wall. 8 He said to me, "Now, son of man, dig into the wall." So I dug into the wall and uncovered a door to a hidden room.

9 "Go in," he said, "and see the unspeakable wickedness going on in there!" 10 So I went in and saw the walls engraved with all kinds of snakes, lizards, and hideous creatures. I also saw the various idols worshiped by the people of Israel. 11 Seventy leaders of Israel were standing there with Jaazaniah son of Shaphan in the middle. Each of them held an incense burner, so there was a thick cloud of incense above their heads.

12 Then the LORD said to me, "Son of man, have you seen what the leaders of Israel are doing with their idols in dark rooms? They are saying, `The LORD doesn't see us; he has deserted our land!' " 13 Then he added, "Come, and I will show you greater sins than these!"

14 He brought me to the north gate of the LORD's Temple, and some women were sitting there, weeping for the god Tammuz. 15 "Have you seen this?" he asked. "But I will show you even greater sins than these!"
16 Then he brought me into the inner courtyard of the LORD's Temple. At the entrance, between the foyer and the bronze altar, about twenty-five men were standing with their backs to the LORD's Temple. They were facing eastward, worshiping the sun!

17 "Have you seen this, son of man?" he asked. "Is it nothing to the people of Judah that they commit these terrible sins, leading the whole nation into violence, thumbing their noses at me, and rousing my fury against them? 18 Therefore, I will deal with them in fury. I will neither pity nor spare them. And though they scream for mercy, I will not listen."