Is God's wrath an anthropomorphism?

In Eastern theology, the idea of a dispassionate God is common. It is often said that wrath is an energy of God but is not part of his essence. I have even heard Western theologians say that wrath is not an eternal attribute of God (it did not exist in the absence of sin, it only exists in response to unholiness). Does he really get mad or is this just for our benefit, since "God is love?" Or is this an influx from Plato into Christian thought? I am interested in a Western explanation (which often speaks of eternal vs. temporal "attributes" of God rather than the Eastern model of essence vs. energies).