Additionally, I reject the premise that CO2 and Nitrogen are pollutants. They are important elements of our atmosphere that are necessary for all life.

I think the reason they're using is that nitrogen from cow pies can seep all the way into the water table thus making it unsafe, especially for those who get their own water via wells etc. Even if that were true, only now it is a problem? Even when they give a credible explanation they still leave room for you to go "wait a minute, but if...?"