This is not bad writing, Superman's wrath has been heavily mediated by Wonder Woman's return.
It's still very bad writing.
Superman took to the solution of murder and Diana has fully supported him. Hell, when he burned Martian Manhunter to death she was right there. Anytime he killed someone she kept telling him he was doing the right thing. If Superman's wrath had been mediated it should have happened when he went face to face with his parents in the fortress of solitude. All Wonder Woman did was break his Yellow ring.
The fact that they did some 180 on their whole moral stance is ridiculous. At least make Superman consistent and not a hypocrite. Oh wait, he keeps telling Batman that he's evil for working with Etrigan, but in the meantime he works with Ares and Sinestro.....