I agree. Violence is everywhere and specifically in the animal kingdom it is weird to apply a moral judgement on violent animals. Eg. the wolf that in nvc symbolizes violent language does nothing wrong when it gathers the food it needs to live. There is no malice however "ruthless" it looks from the outside. And the giraffe also does nothing wrong when it protects it's grounds by kicking a hyena's head in.

But we humans that use these animals as metaphors when trying to improve our communication skills can apply a moral judgement and say that this way of communicating is better than that way. But we literal minded often get derailed when the metaphors are not 100% solid so I often think that metaphors are bad, or at least risky. (but I like these specific metaphors in nvc somehow)

I agree with your first and last point, but surgery != violence.

I disagree, but we are quickly getting deep into semantics.

Surgery is not a harmless procedure. But the surgeon must decide that the patient is more likely to benefit overall from it.