The film, directed by Bennett Miller, has been nominated for Golden Globe, SAG and Critics' Choice awards with hopes to perform well at the Oscars as well.
Mark, a gold medal-winning Olympic wrestler, took to Twitter and Facebook to fact-check the script and rant about Miller and the film.
Mark had previously indicated his support for the film but he became angry when some critics commented about an undercurrent of homosexuality in the film's portrayal of his relationship with his coach John du Pont, played by Steve Carell.
"The personalities and relationships between the characters in the film are primarily fiction and somewhat insulting. Leaving the audience with a feeling that somehow there could have been a sexual relationship between duPont and I is a sickening and insulting lie," Schultz wrote on Facebook.
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"I told Bennett Miller to cut that scene out and he said it was to give the audience the feeling that duPont was encroaching on your privacy and personal space. I wasn't explicit so I didn't have a problem with it.
The title of the film comes from the Philadelphia estate where du Pont set up a training camp that attracted wrestlers such as Mark and his celebrated brother David, played by Mark Ruffalo in the film.
John du Pont had exhibited bizarre behavior for an extended period preceding the murder of Dave in 1996. John du Pont died in prison in 2010.