One of the hallmarks of a strong, well-functioning democracy is the existence of clear, easy-to-understand laws. Indeed, one of the hallmarks of the US Supreme Court is the idea of stare decisis. Stare decisis is just a fancy phrase for the idea that people should be able to rely on the laws as they exist, based on precedent, and that drastic changes in interpretation of the law should only be undertaken in extraordinary circumstances. People build families and businesses based on the law, and if the law isn’t reliable, it will hurt people.
The NFL is, of course, a poorly-functioning monopoly, and as such, they are littered with muddled, unclear laws open to wide interpretation from semi-incompetent hereditary monarchs.