Rulings like this annoy me. Like, if he had said "the spell is poorly written, because our intention is that a wall of force can be targeted by disintegrate, but you're right that that's not what the spell descriptions say", then I'd be able to respect that a lot more than what you describe him saying.

Words are a slippery beast, and there will always be a gap between Rules as Intended and Rules as Written. Good game design can reduce that gap, but not if the designers aren't willing to acknowledge the chasm they have created