They don’t have the duty, or the ability.
That’s kind of the key. If the police have two competing situations and can only respond to one of them, say a large accident with injured people and a lady calling about her restraining-order ex (which, in most of those situations, doesn’t end violently), do we want the decision as to which is priority to be based on keeping from being sued?
...easy solution, the woman needs to arm-up and know how to use them. If nothing else, shooting a few rounds, even if they miss, will push her way up in the police-priority order.