First, there is a difference between destroying government documents and destroying personal or private documents. And last time I checked, the NFL wasn't a governmental entity.
Second, destruction of document only has application if a legal investigation has been initiated. Then if one destroys documents critical to an investigation, it becomes a criminal matter. Godell's actions had nothing to do with a criminal or civil investigation.
Third, Specter's comments make little sense because banks and corporations destroy records all the time. The only time it would become an issue is if the companies were notified of an investigation and were specifically told not to destroy evidence crucial to that investigation.