Ignoring posts really isn't the problem, nor would be ignoring a person. It is as Poisen pointed out that a person's mere presence can cause troubling emotions within a person. We can ignore them all we like, but we cannot force ourselves to foget that they are present no matter how hard we try. I can understand this from a real-life perspective, as well as on boards.
Just being around someone who has caused you some terrible emotional pain can be torture, I know this personally because someone traumatized me when I was a teenager and I was never able to get over that pain to any extent until I had moved over 300 miles away. Even now when I'm not around that person just the thought of them still causes me some anxiety, but not the terror or pain that they had once wrought. Its a pschological thing, and those type of wounds do not heal as easliy as physical ones. Its been over 7 years now for me, and I still feel the pain to some degree from my own.
This is something that the individuals involved will need to tend to on their own with counsel from friends if they will allow it. But, because it has left its imprint in our community we as a whole should best decide how to deal with it here to hopefully prevent such things from happening in the future, if at all possible.