In political terms this would be called a "log-roll." The HOB recognizes that they're in trouble, and this is in a sense a surrender. However, they also took pains to remind the Primates that nothing at all is going to happen until GC06.
The subtext to this is that the HOB is fully expecting GC06 to forge ahead with the public affirmation of same-sex blessings -- so all they've really done is try to kick the can down the street a bit longer.
Note that the HOB quite clearly stated that they would take no action against those bishops and clergy who continue to practice "non-public" rites for same-sex unions. This is the real meat of the statement, and I think the Global South will pounce on it.
I think the HOB made a big mistake by asserting the "no consecrations whatsoever" policy. This is clearly wrong-headed -- it's essentially a confession that the ECUSA no longer has any clear idea of what a bishop should look like. This, I think, will provide fodder for the Primates to state that the ECUSA has utterly lost its way.
I disagree with the first statement here. Their idea of what a bishop should look like is clear to them; no one should be excluded from the episcopal office on the basis of race, gender, or sexual practices with other consenting adults.
The HoB probably (and quite rightly) figures that the Primates will force a move if another homosexual in an active sexual relationship is consecrated Bishop in the ECUSA. So, they can't consecrate such a person as Bishop; it's entirely possible that such a person will be elected and approved as a Bishop in some Diocese or another before GC2006; and to withhold consecration of such a person while proceeding with a consecration of someone not so classified would cause cries of "injustice" from the proponents of such a thing. On that basis, they believe it to be only fair to refuse to consecrate anyone until the matter has been resolved at GC2006.
I find the whole comment of "The HoB is only one house of the ECUSA polity, and they can't do anything on their own" quite bogus. The bishops are the chief shepherds of the ECUSA; they can certainly control their own actions until the whole church can discuss it. By refusing to consecrate any bishops, they are doing exactly that here.