Is it wrong to get angry with God when reacting to other people’s injustice? I feel that such a reaction is natural.
Even though it may seem natural to you, your getting angry with God (over injustices which you experience from people) is not good theology. If God is all holy and sinless, then your forgiving God implies wrongdoing. I prefer keeping a sound theology and understanding that God allows for the free-will actions of people, even if those actions are unjust. People are the ones who behave badly, not God. Rather than forgiving God, I suggest that you try to practice acceptance of what is allowed and then to forgive persons. In this way, you do not diminish the attributes of God.