Imagine a person who is likely to kill/harm you in a fit of passion.
If the harasser could get carried away in an argument and start beating, but didn't leave the house planning to kill, then restraining orders can limit the time the harasser is around you and limit the time before they 'blow their cool'. When the harasser breaks the restraining order and comes near you "just to talk, I promise", you can get the police involved straight away, and the harasser can be hauled off before they lose their cool, and things escalate.
So you get a restraining order and when they approach you just to talk anyway and you call the cops to come arrest them because they were not following the restraining order then they go into the same murderous rage. I am really not seeing how it is helpful, it would be illegal for them to harass you anyway.
If the harasser could get carried away in an argument and start beating, but didn't leave the house planning to kill, then restraining orders can limit the time the harasser is around you and limit the time before they 'blow their cool'. When the harasser breaks the restraining order and comes near you "just to talk, I promise", you can get the police involved straight away, and the harasser can be hauled off before they lose their cool, and things escalate.