Because the principals can still make references to one another, can still post in the same threads commenting on each other to other parties, and so on and so forth.
Co Existence to me is more along the lines of avoiding certain topics, ignoring as best as possible attempts to flame or bait as well as avoiding the temptation to do the same.
Things can get inflamed without direct posts to one another. As we've already seen.
It seems that there are some jagged emotions at work here, and it might be best for some to just take a break, assimilate and try to figure out a way to truly reconcile in some fashion. Generally the people at this forum are people of faith. Here is an opportunity to walk the walk.