Background: Monty Kip Sopp (born November 11, 1963), better known by his ring name Billy Gunn, is an American professional wrestler, former professional bull rider, and singercurrently working for New Japan Pro Wrestling (NJPW). Gunn is best known for his appearances in the World Wrestling Federation/Entertainment (WWF/E) from 1993 to 2004 and from 2012 to 2015. He also served as a coach on WWE's Tough Enough, and was a trainer in its developmental branch, NXT. He is also known for his appearances with Total Nonstop Action Wrestling (TNA) from 2005 to 2009.
Context: On February 13, 2005, Sopp debuted in Total Nonstop Action Wrestling (TNA) without a name (as Billy Gunn is a WWE trademark, although announcers recognized him as such) at Against All Odds with the same gimmick, helping Jeff Jarrett retain the NWA World Heavyweight Championship in a match with Kevin Nash. Sopp, using the name The New Age Outlaw, then formed a stable with Jarrett and Monty Brown known as Planet Jarrett. However, WWE threatened TNA with legal action if Sopp continued the use of the name "The New Age Outlaw", so he shortened his name to The Outlaw. Due to the legal issues with WWE, all TNA DVD releases featuring footage with Sopp as "The Outlaw" (and presumably also as "The New Age Outlaw") have had the name on on-screen graphics blurred, the name silenced out of the audio, and match commentary completely replaced to reflect a retroactive name change to "Kip James". One such DVD is the pay-per-view Lockdown, included in the "TNA Anthology: The Epic Set" box set, in which the silencing of the name during a segment where Dusty Rhodes picks his name from a lottery leaves DVD viewers in the dark as to who just got picked.  The Outlaw began a campaign to make former ally B.G. James leave the 3Live Kru and defect to Planet Jarrett, reforming the old tag team with Outlaw. At No Surrender (2005), he renamed himself Kip James and was announced as "wrestling out of Marietta, Georgia" (the family seat of the Armstrong family) as a psychological ploy. As a result of his campaign, Kip attracted the ire of 3Live Kru members Ron Killings and Konnan, leading to a series of tag team matches pitting Kip and Monty Brown against Killings and Konnan, with a conflicted James unwilling to take sides. Kip's efforts ultimately proved futile; James, the guest referee in a final match between Brown and Kip versus Konnan and Killings at Sacrifice (2005), attacked Kip enabling a 3Live Kru victory.  In September at Unbreakable, Kip teamed with Brown to defeat the team of Apolo and Lance Hoyt. There was clear tension between the partners because Brown was unhappy at the series of losses at the hands of the 3Live Kru, and Kip was irked by Brown's decision to leave Planet Jarrett. Despite the victory, the partners argued after the match. On the October 8, 2005 episode of Impact!, Kip rekindled his feud with the 3Live Kru, running to the ring after a bout between the 3LK and Team Canada in order to prevent Team Canada captain Petey Williams from beating down B.G. James. He saved James, and then engaged in a staredown with Konnan and Killings. Kip saved James from Team Canada once again at Bound for Glory. Though Killings showed signs of gratitude, Konnan remained skeptical as to his true intentions. Later that night, Kip took part in an over-the-top-rope gauntlet match for the number one contendership to the NWA World Heavyweight Championship. After he was eliminated, he tried in vain to prevent Killings from being eliminated as well, before being sent away from ringside by the referees.
Question: Why did they threaten legal action?

Answer:
Billy Gunn is a WWE trademark,