Is God Unjust?

When I read Ahnsahnghong's book The Mystery of God and the Spring of the Water of Life, I was quite surprise to see that he made a statement referring to God as unjust. It was when he was talking about his idea that we are all former angels, which is one of the major doctrines of the World Mission Society Church of God.

On page 337, Chapter 25 (of the copy I read), he said:
"Ordinary people are the angels, or the holy people of heaven, who sinned and were born as men; they were driven out from heaven because they rebelled against God, being tempted by Satan. Among them, some sinned unintentionally, being tempted, and were unjustly accused and hurled to the earth. To seek and to save them, Jesus Himself came into this sinful world."

So, apparently Ahnsahnghong thought that in heaven (where God would reign supreme, right?) some of the angels were unjustly accused and cast down to Earth.

Doesn't that sound to you like he's calling God unjust? That God made an unfair judgment? The alternative would be that God was not in control of the goings on in heaven, and that certainly can't be right, can it?

The Bible says that God is most definitely just. It's part of His character. We, as humans, may not understand His judgments or reasons for allowing things to happen, but that doesn't change the fact that He is a just and righteous God. Here are a few of the many verses about it...

Deuteronomy 32:4
"He is the Rock, His work is perfect;
      For all His ways are justice,
      A God of truth and without injustice;
      Righteous and upright is He."

2 Thessalonians 1:5-6 (NIV)
"All this is evidence that God's judgment is right, and as a result you will be counted worthy of the kingdom of God, for which you are suffering.  God is just: He will pay back trouble to those who trouble you"

Revelation 16:7
"And I heard another from the altar saying, 'Even so, Lord God Almighty, true and righteous are Your judgments.' "

So why would Ahnsahnghong call God's judgment "unjust"? I haven't gotten a good answer about that yet.
The obvious answer I see is that God CANNOT call Himself "unjust", therefore Ahnsahnghong is NOT God.