He said the proprietors had never taken the sorts of risks they had urged on British service personnel in calling for the war.
Speaking during a debate at the festival on media coverage of the war in Iraq, Mr Bell, who was a commentator for Channel 5 during the conflict, also attacked Mr Murdoch's Sky News for the amount of speculation it indulged in and for "reporting rumours as fact".
Mr Bell said: "The thing that worries me most about the coverage was its feverishness. The networks became rumour bazaars. There was spin and manipulation. Our political and military leaders also have an obligation not to deceive."
Alan Rusbridger, the Guardian's editor, told the thousand-strong audience that technological developments had enabled the immediate transmission of pictures and information.
They allowed the internet distribution of thousands of sources of information, including from the so-called Baghdad Blogger.
Another aspect of this war was the use of reporters who stayed with particular troops during the conflict, "embedded" in military units.
"It would be churlish to rubbish the concept of embedded reporters, having asked for it in previous conflicts," he said.