There is some truth to this statement - Many Operators on the ground were against this decision / plan - (yet higher-ups pushed it through).
With that said, it was obvious to all that a certain level of cleansing was surly needed within the ranks of the former Iraqi Army before allowing others to stay on the job.
This was a tough call from the start. But it was definitely made farther up the chain of command then it should have been (at least in absolute terms).
Wolfawitz was behind disbanding the Army mostly because Chalabi convinced him it was a good idea.