...I seem to remember that FE felt that allowing posts to be altered later might let alterations change the meanings, thus ensuring a never ending stream of arguing along the lines of "You said that, before you altered it later"...
That's a bit of a non-argument really. In keeping with most other forums there could be a timer on the edit function to say 5 or ten minutes. I think it's to do with something else.
Actually, it's the right answer. Unlike lots of other forums, discussions in this one can move at a very fast pace. If we had a five-minute edit delay it would give rise to no end of problems, as people responded to something that was said in a post, only to see it changed, almost as soon as they posted.
It's the reason we don't have an edit facility, and it's the reason we're not going to have one. We've tried to help by providing the preview panel underneath the text entry box - it shows you exactly how your post will look when it's online.