I think you miss rayiner's point. He's not disputing whether CO2 is a greenhouse gas. He's saying that doesn't make it a "pollutant" as the term was understood at the time, say, the EPA was created. There was no congressional legislation that said that it was something the EPA was empowered to regulate. Then the EPA decided to regulate it anyway (and, yes, won the court case about whether it could). But it was still shoehorned in, as it was not considered a pollutant in the way that NO2 or particulates or chlorine were.