If the machine is constrained to not thwart human desires, and one of our desires is to not have our desires modified, then the machine will have to break its constraint to arrive at the solution you indicated (rewriting human desires). The ability of humans to defend themselves is beside the point.
I've rewritten 4.4 for clarity since you left your original comment. Do you still think it needs improvement?
I wrote a new Singularity FAQ for the Singularity Institute's website. Here it is. I'm sure it will evolve over time. Many thanks to those who helped me revise early drafts, especially Carl and Anna!