There are many factors that can lead to cancer. A strong factor in throat/esophageal cancer is consumption of hard liquor. Hitches was a noted alcoholic who appeared drunk at some of his speaking events.
Esophageal cancer: Alcohol consumption is a major risk factor for a particular type of esophageal cancer called esophageal squamous cell carcinoma (2). In addition, people who inherit a deficiency in an enzymethat metabolizes alcohol have been found to have substantially increased risks of alcohol-related esophageal squamous cell carcinoma. Alcohol fact sheet at cancer.gov
Hitches spent the last years of his life sucking up to George W. Bush and the people around him. He became an acquaintance, if not a friend, of Dick Cheney.
To me the definition of a flawed argument is the defence of the second Iraq war and Hitchens was, to the end, a defender of the war. Obviously I’m not a Hitches fan.