He didn't rip Murtha, but Irey's campaign has done an adroit job of connecting his statements to Murtha's cut-and-run demands.
You're absolutely right -- this is an astonishing press release. I've read the book from cover to cover already, and I can tell you, the author does a remarkable job of putting together the indictment against the Bush Administration and its handling of the run-up to the war and the execution of the war itself, and its aftermatch. Nowhere in the book itself does he come anywhere close to ripping Murtha; in fact, the author's arguments about how we got into the war and what the Bush Administration did wrong in its execution of a war plan track exactly with what Murtha has been saying.
Nevertheless, it is true that he said on MTP what Irey says he said. After walking him through everything the Bush Administration did wrong from start to finish, Russert then closed the interview by giving Ricks the chance to discuss future options. And Ricks just slammed the door shut on immediate withdrawal, calling it "irresponsible" and "shameful."
You say "adroit." I say "clever." :)