That's a reflex, which is different from an instinct. In any case, I think the rather creative behaviors of hurting people in this case are obviously learned.
Humans are just another species of animals, why wouldn't they have an instinct? The only difference is the cultural conditioning, which suppresses instinct behavior.
Because humans have such a capacity for learning, instincts would serve no purpose. Instincts are rigid and humans on the contrary are very adaptable. It appears to me that the scientific consensus is that there are no human instincts, but if you believe otherwise why don't you cite an example?
Well again I'd say that's not an instinct, just like hunger it's a desire. An instinct is a very specific pre-programmed behavior that can't be overridden, a desire or reflex doesn't fit that description.