By media, I assume you mean the US Government since they are the ones who have done the most extensive study of brain injuries due to concussions and have concluded that repeat concussions can cause serious brain damage. Since the government really has little to gain by concluding this unless they want to give out more disability (something I know they don't like since I am a DAV) , I'm going to go with them and not your very scientific "doubts" based on what appear to be normal people for the hour or so you see them each week.
The bottom line is that concussions are a real problem as are low shots to the knees. Trivializing (and yes, when you make generalizations, it's trivializing ) it because you don't like the results isn't the solution to the problem.