These mobile suit bodies may only be machines in the form of humans, yet seeing them reduced to scrap has a powerful effect on me. The few times Zeta indulges in flesh-and-blood gore, the effect is repulsive. Yet the broken machines fascinate me.
I think it's the abstraction in the horror. Where a corpse would be grotesque, a wrecked machine is not. But on some level we still understand that the machine is the person. We can soak in the tragedy of the scene.
Machine gore is rarely shown at the moment of injury - it appears in the stillness after. We are not insulated by shock, fear, or even excitement. This allows us to experience subtler horrors.
Crushed and broken bodies in the ruins of shattered homes, on pulverized streets. A son watching the machine that became his father's body and then his coffin dissected for parts.