I am really sorry that regular posters feel like this about these events, but I think this is a bit trickier than it appears on here, isn't it?
I was around for all that stuff and I have read the blog in question more or less ever since. I don't believe that person was a troll in the way it is being made out here. She may have been a troll in the past and she certainly has a very raging, angry perspective on the world which she may have had ever before suffering a bereavement. However, she did lose a child and I understood the blog post she wrote. I saw it as deeply tortured and anguished and I can imagine it must have been very difficult to be included in it.
I don't read the bereavement thread but I did look at it via that post, and I also can't imagine the pain it would cause you to read people discussing how your loved, dead child never existed and that you made up the suffering you shared for fun. I remember the day that she was "revealed" because I was on the thread where it happened, and ironically, RL friends with one of the posters she then spoke about in her blog... and I was initially, like many regular MNers shocked and appalled that someone would make something like this up... but over the course of that thread it became certainly apparent to me that nothing had been made up but a lot of people were getting a vicarious thrill out of tearing this woman and her writing to shreds.
To me, it seemed it was a terrible and unfortunate confluence of events that led to the recent posts that were so upsetting for you both but there is real pain, suffering and bereavement here on both sides.
It's not actually a simple matter of a troll getting a kick out of dabbling in bereavement groups vicariously because they have, say, some other mental health or personality issue, is it?
At the same time, I understand why she is banned and perhaps needs to remain banned despite the unfortunate way this whole thing happened in the first place. I don't think it is healthy for her to be posting here but in some ways I think all mention of this should be banned too, because really, it's just not that straightforward.
Sadly, it is also true that this is a public forum and everyone's hearts are out there on a line no matter how much somewhere seems like a safe haven.