As bala already mentioned, the networks do have censorship and can only show certain content. They will get fined by the FCC if they don't follow the regulations. Showtime and all of the other pay cable channels do not have to obey these and can show the type of graphic content you were talking about. Secret Diary of a Call Girl, Weeds, The Sopranos and The Wire can be as graphic as they want to for this reason.
Because I do not like "real" horror films, I thought the first story was pretty intriguing. It moved right along (as the show is only 45 minutes) and the horror level wasn't bad. The end was very good... I wish networks had these types of things (i.e. anthologies, horror type shows)... This summer, I need this type of stuff to keep my schedule alive. If it gets canceled, I'll be saddened. US users can find full episodes of Fear Itself on NBC.com and Hulu.com (as I did).