I think you might be close as to why some bloggers don't necessarily hang with us here at the Council, but I have a sneaking suspicion that there may be another reason as well: control. On their blogs they have total control, and there really isn't any discussion in the sense that we have here. They can turn off (or ignore) comments, which don't even necessarily show up on the main post unless you click on a link. Here they can't do that.
Actually one of the reasons AM cited is that the blog comments over there got quite out of control. I used to go to AM for the excellent commentary and discussion, same as why I come here, and lately the place has been overrun by a rather strange bunch, often from varied political sites, who I think drove off a lot of the better commenters.