This is a logical extension of the job Kallstrom did for the FBI. Diseminating disinformation to avoid public panic, while working in the background on the real problem.
I'm sure by reassuring the Sheeple that TWW800 was NOT a terrorist attack, he learned much in how to control the New York missile witnesses. Skills that should come in handy if any New Yorkers witness a subway attack. "Only cleaning solution was used. Nothing to fear. Move along."
You can sure tell Pataki learned his politics before there was an Internet. This will have the opposite of the intended effect. People will doubt everything he says. Kallstrom could say the sun rose on time and people would double-check.