It is not only people in prison or people in abusive relationships that use that word. It is a commonly used word among American youth, It is often used in a comical way (see "I'm Rick James, bitch!), it is often used in an affectionate way between friends, and it is often used in a harmful way.
Your personal tragedy does not give you ownership of the word. It does not give you the right to dictate the way that society uses that word. People will continue to refer to their friends, enemies and victims as their bitch no matter what you or I think of it.
I was the one who objected to the use of "bitch", not Katherine. As someone who comes from the half of humanity that is disparaged by this use of "bitch", I don't need someone in the other half of humanity to tell me that people will continue to use sexist language whether I like it or not, and that I don't have the "right" to "dictate the way that society uses that word". I'm well aware of my lack of both rights and power in this area. But you
don't have the right to tell me that I may not call out a sexist use of language when I see it. And it doesn't matter if the person using this term in this instance didn't create all the sexism attached to the meaning of the term (when was that ever the case, with an offensive term?). It doesn't matter if it was used just because it's a handy label. It is a sexist term that perpetuates sexist attitudes. If you don't give a damn about that, certainly, you have the "right" to continue to use it. If you do give a damn about that, then choose a different word.