The BBC has replied to my complaint. See below.

Dear Mr Lee,
Thank you for your email. The news story you refer to was written on
Sunday 13 January, while I see the comments by John Edwards that you
refer to were reported by CBS on 11 January. That is a different
situation and different story. We have not excluded Mr Edwards as you
allege. The story we were writing was about the row between Mr Obama and
Mrs Clinton.
We have repeatedly covered Mr Edwards, his campaign and his comments and
shall continue to do so.
We are, of course, taking a broader brush to our coverage than the US
media who have the resources, the interest and the task of covering so
many more angles than us.
Kind regards
BBC News website