Maybe because those buying are doing so based on the knowledge that the next few months will be replete with all sorts of hail mary saves for the banks and anyone else with their hand out. Listen to what Geithner is saying, they are going to pull this thing up by its bootstraps, and use a crane to do it if necessary. The bond market is hearing him loud and clear.
Oh, yeah: "The gap between our citizens and our Government has never been so wide. The people are looking for honest answers, not easy answers; clear leadership, not false claims and evasiveness and politics as usual." -- Jimmy Carter's Malaise Speech, 1979
Since October 10th we've been in a trading range of 8-9k on the dow. We're due for a rally to the top of that trading range.