The NFL is just the organization to oversee fair operations between the clubs themselves. Personnel issues should be above their pay grade. The franchises I've been involved with have never stepped into personnel issues. The ones within the actual company, on the franchisee level, are the ones that handle those matters. The franchise, the higher corporation, just manages the systems and making sure the overall operation is up to snuff.
If the clubs want to look into player misconduct, I'm fine with that. The league, in my opinion, is overstepping their boundaries.