John Mayer is insisting that James Cameron was wronged by the man seeking his autograph on an 'Avatar' poster at LAX. After TMZ posted a video of an alleged "fan" being snubbed by the famous director, Mayer wrote a nearly 1,000-word essay on his blog titled 'The Anatomy of a Smear: How The Reigning King of Special Effects Got Caught in One,' which defended Cameron's actions. According to the video, Cameron is seen telling a man, "I don't owe you a f---ing signature ... just get out of my f--king personal space." But Mayer says it was misinterpreted as Cameron being rude to a fan when really the "fan" was a pushy, media savvy "Obnoxious E-bay Poster Guy" who felt entitled to make money off the Oscar winner.