To carry Krugman's insanity to its illogical conclusion, criminals and arsonists who destroy property are doing yeoman's work for the administration by creating demand for products and services where none existed before.
And what of the murderer who creates work for police, judges, prison guards, morgue workers, undertakers, grave diggers, florists, casket manufacturers and others?
As pointed out in post #4, Krugman's entire house of cards is built on his faulty first assumption - that money spent repairing a broken window or replacing a burned out home was just sitting around unused and would not have been spent had the criminal or arsonist not manufactured demand.
Post #5 sums it up nicely - he is quite insane.