So if I don't swallow hook line and sinker studies that are acknowledged to be biased I'm a stooge for the NFL? 
I don't even love football as much anymore but the point is until we have a bunch of brains of people who aren't showing symptoms we won't know for sure it's CTE that's made some "go crazy" because maybe 97% of brains from all players show CTE and only a small portion actually "go crazy", or maybe the majority won't show any CTE who knows but we can't say anything definitively until broader studies are done is all my point was.
Study is not biased. They just don't have brains from "healthy" players to study. See half smokes comment. If the rate is like 10 percent that is about 10 players on the field on any given Sunday. In the next ten years or so you will see football start to disappear at the high school level.
