The ongoing battle between “organic” and “synthetic” products has been raging for some time, and undoubtedly will for many years to come. It generally comes down to a case-by-case question, as to which is better.
But when it comes to fertilizer, there is very little argument. Synthetic chemical fertilizers are outright harmful to your lawn and to the planet itself, with very few arguments in favor of their use. There might be some merit to the notion of “better living through chemistry,” but when it comes to the natural cycles of growth on Earth, there really is nothing better than natural organic fertilizers.