Why can't Hicks tell his story of woes in Gitmo?

Why is it that in a country where "Freedom of Speech" exists, somone can be told that they are not aloud to speak to the media for a year and can not write a book describing his life? How is this tolorated in America? Especailly when this man's story could very well give great insight into the inhumane and cruel punishment recieved by detainees at Guantanimo Bay Cuba!