I'm very conscious that you have been through a lot and I don't want to make matters worse.I guess from reading this stuff, I have been through a lot, but don't worry, as long as people are respectful and talking about their own experience, its fine. I didn't put this stuff up for sympathy or advice so much as to wonder if other people have been through the same sorts of things with their ptsd.
I've worked through a good deal of the shame issues I talk about in the post, very much along the lines you map out. One other thing I learned was that taking on other people's shame is a way of trying to gain control of the traumatic events. If its me, I have an explanation, and maybe even a solution: If its my fault, it might be under my control to change it somehow.
Of course, this is an illusion, one that gets reinforced by 12-step work, which encourages people to always look within for the source of our troubles: The only way it makes sense is if I am just somehow utterly broken goods towards whom such behavior is natural. This was reinforced by my abusers big time (who were, not coincidentally, all associated in one way or another with 12-step forms of recovery), and opting out of that illusion has been key to getting better. It is very tempting to revert to it though, in order to have a reason for things other than that people who I trusted and believed in were malicious and untrustworthy. Its a perverse sort of way of maintaining my old view of the world and denying the betrayals that took place.
When this self-shaming takes place now, I am usually aware enough to take a step back, separate myself from my abusers, and recognize that I am trying to make sense of things in a self-destructive way. The betrayals and abuses were real, and they are not mine. As you say, that then leaves me more freedom to deal with the strong emotions connected with the events, which though they may not be pleasant, they are at least somewhat healing.
I guess sometimes I still shy away from dealing with these emotions because when they all came out at once, it was totally overwhelming and destabilizing, so I need to have support and stability to let go of the shame. While it may be a dysfunctional and ultimately self-destructive way of coping, I needed to recognize that coping is what it was about, not some defect on my part, which of course would only reinforce the shame.