Why can Hulk Hogan use his name anywhere?

Hulk Hogan has the rights to his name & can use it in any way he wants. He's been using that name in the ring for over 30 years & he's used it from his days in AWA, WWE, WCW, New Japan Wrestling, & now currently signed to TNA Wrestling. He's allowed to use it because he has the legal rights to do so. For Scott Hall & Kevin Nash, they couldn't use the names Diesal & Razor Ramon in WCW because the WWE (which was the WWF at the time) has the rights to those characters so they couldn't carry over the characters when they jump ship from Vince McMahon's promotion to a promotion once owned by Ted Turner. The WWE cannot sue TNA for copyright infringement of Hulk Hogan's name because Hogan owns the copyrights of his name.