It's pretty simple, really. There actually are a lot of stupid people in America. It seems worse than it is since it's the stupid people who end up on TV and Youtube, but there are still plenty even without the exaggeration and skewed viewpoint. Since we have a government "of the people," and since you'd have to be some sort of moron to want to be a politician, stupid people end up in the government and we end up with things like turkey guidance.
Also, since that guideline probably came from the Department of Agriculture (USDA), no they don't have better things to do. That's actually their job, amazingly enough.