That would be fairly tame among freeps, who generally hope for a political victory, not a second shooting Revolutionary War.
The reason that tale keeps coming up is because of the belief that the WTC attack was an inside job.
The evidence is to the contrary of course.
Some people will never believe there are Islamic Arabic speaking fanatics who imagine they can bring America down by blowing up a building.
Now, does their lack of belief constitute evidence of madness? Others imagine there's a carburetor that will give you 100 mpg. Are they nuts, or are they members of Congress?