I find it disappointing for the administration of an instance to be "against harassment" but only if said harassment is in-house.
If, by your own logic, death threats were okay as long as they did not originate from your own instance, then I could say whatever I wished to you, yourself, and nothing could be done because the call wasn't coming from inside the house.
Do what you want with the feedback you've received from the critics of how you've fumbled this situation. Dismiss us all as haters, or claim that because this user hasn't caused problems for you ~~yet~~ that she never will (and tbh I wish that you didn't ever have to deal with this either, it isn't like we're having a great time over here cleaning this mess up
) I'd just hope that for the sake of everyone over at AllThingsTech you'd use this as a cautionary tale, and maybe act as the responsible administrator I used to think you were.