"Muting" does nothing more than allow a user to control what he/she sees on his/her own screen.  I don't think the flaw is between Disqus and CivilComments but in the actual blocking programming CC implemented, which blocks an entire thread where a mutee's comments appear, rather than just the mutee's comments.  I've written a number of times to ask for this very simple change -- perhaps if others took 2 minutes to also request this minor change we would have a more workable system.  Practically speaking, not even seeing posts from those you know (by history) to be personally offensive is really the only defense we have in a comment forum.