I don't know if I'd consider WHM "good." Lore-wise, I'd put them rigidly at Lawful Neutral.

Reasoning:
They submit to the elementals completely (Law), and that means whatever the elementals say. Including letting people die at their will, or turning another cheek to outside problems entirely, as you see in the 50-60 WHM quests when the "good" option would have been aiding them. They finally snap out of it in the level 60 quest because the Warrior makes them, but it takes basically the entire forest being threatened to even consider action.

Also worth noting:
WHM and BLM are fundamentally similar. White magic caused the an Umbral Era just as much as Black Magic did, White Magic has been used more destructively in the past, just as much so as Black Magic. There's a reason it's banned.