An occasional column in which the Los Angeles Times invites outside critics to wallop a Southern California newspaper, even when it has a new editor and a new publisher who would no doubt prefer a bri ------------ I CANNOT IMAGINE what it would be like to lose my child the way Cindy Sheehan lost her son, Casey, in Iraq. The bereaved mother, who until Thursday had been camped outside President Bush's ranch in Crawford, Texas, has every right to protest the war, and her demonstration was certainly news. But in its apparent zeal to portray Sheehan as the Rosa Parks...