I feel for that women but that case presented is self defense. She was removed from the immediate danger and had non violent options but planned out a violent attack. She took the law into her own hands by getting people to kill her husband.
I don't think the author makes a good case for this being self defense law failing women. This seems to be more that domestic violence law sucks and police were inept at supporting domestic violence victims. I would like to think that has improved nowdays with the domestic violence ads and messaging that gets put out.