Oh. My. God.
This brain doctor who writes in Yahoo! Sports about football and traumatic brain injuries and chronic traumatic encephalopathy fails the basics of epidemiology. He reminds me of people (like Vice President Mike Pence) who say that since only a small percentage (around 25%) of people who smoke get lung cancer, there is no link between cigarette smoking and cancer. But what researchers have found since the 1930s is that of people who get lung cancer, most (80% or more) smoked cigarettes.
He says the fact that others get CTE when not playing football is part of his reasoning. But that is irrelevant. People get cancer from causes other than cigarettes too.
Wow. Maybe this guy should have been an engineer.