I've seen you mention this a few times:
I think THAT hurts more than anything...Im crying over her loss, but if the tables were turned, I guarantee she wouldn't do the same for me.
You're right, she wouldn't do the same. She was unfortunately a broken person. It wasn't personal to you even though it felt that way. I can see that it impacted you in that way though, and it hurts. Again I'll encourage you to try to understand her because it will help set you free from some of that. But that comes later. Right now you're probably angry, another step in the process of grieving, and that's okay. Be there, feel it, let it out, and you'll get to a point of greater acceptance later.
my little sister - was an adult who CHOSE not to have me in her life. She chose to make this decision to be separate and not include me in she or her childs life.
I think that the element of choice is seen so black and white, without all of the levels that go into things, and that because of that it hinders understanding of another. She was under the influence of brainwashing and a personality disorder, so choice is relative to those things. Jehovah's Witnesses teach that everything is a matter of choice, and by doing so they get to moralize everything and then judge. Your sister didn't choose to grow up in a cult, or to have BPD. You didn't choose to have a sister with those issues. Looking back lots of us acted in ways under the cult influence that we would never act like as a free person. Your sister was never free. She had multiple influences, including that of a personality disorder, one of the hardest things to even begin to treat in any therapeutic setting, something that has a higher failure rate than success at any level.
I think that sometimes our perspectives contribute to the pain we experience. Again though, while in anger isn't the time in all likelihood to challenge those things. Maybe I shouldn't even be saying anything now. I don't want to make it worse or make you feel like I'm coming at you. I hope that later, after some time, you can sit down and re-read things written here, whether by me or others, just different perspectives, and get back to some of the places of acceptance or even forgiveness that you were in at one point and time.
I truly am sorry. Pain has a way of trickling down to everyone. She had a lot of it, clearly, and she transferred it to others, made it their pain. Your sister was who she was, for better or worse, and nothing could change that even when she was alive. That's why I put forth that definition of acceptance, letting go of the hope that things could have been different, because I see you held onto that hope for a long time and now that she's gone you're feeling the weight of that hope collapsing. She was never going to be able to be a friend or sister because she was just so hurt and the illness had her more than she had it. It's a shame. I'm so sorry.
I hope that, in time, you find more peace.