God's anger is supposed to be righteous anger. So, if something happens that seems to represent God's anger, some natural cataclysm or a defeat in battle, we then believe we can deem that event righteous. We attack those we see as our enemies and if we are victorious, we claim that our cause was righteous, thereby justifying our own violence and anger. Then we point to these many, many Biblical passages to further support our claims.
Perhaps all that bile is not there as a justification for anger and hatred and vengefulness. The Bible is still brought to us through human instruments. Perhaps those angry, vengeful passages are there simply to acknowledge the presence of such feelings in the fabric of human life. To hold a mirror up. When we see God that way, maybe we're trying to see him too much in our image.
Of course, that explanation flies in the face of those who claim the Bible is the inspired word of God, that the human instruments who recorded it didn't impact, filter or obstruct the divine messages it contained. I don't take that view.
Like it or not, the Bible was written, compiled and translated by humans. That's a lot of layers of flawed humanity between us and the divine.
I can understand righteous anger, the anger I feel when I see what I believe is wrongdoing. The problem is when humanity takes righteous anger as our due, it doesn't work. Anti-abortion advocates believe their anger is righteous. The religious zealots behind the World Trade Center attacks believed their violence was righteous. Nearly every army who has ever fought a war and won has claimed God was on their side. We humans just can't get it right.
Does this mean I've made God into some sort of wishy-washy warm-fuzzy universal energy? Do I discount the true notion that God might get angry or vengeful? No. But I think we human beings have to be awfully careful not to assume we know what makes God angry, not to try to wreak vengeance on God's behalf, and not to believe that we ourselves have the right to engage in the kind of vengeful, righteous anger that would make us equal to God. We are not God. We can't see into another person's heart.