Brain damage in football is not a risk, it is a guarantee.

You really have to get specific to talk about this. What level? How long is a person participating? What degree of damage are we talking about? Someone who played a year or two of junior high football will not have the same outcome as a 10-year NFL veteran, and plenty of the latter will have damage of a type that is bad, but not debilitating. If people know what they're getting into, there's a real question about how different this is from having chronic knee or back or shoulder problems from playing other sports.

And while we're comparing this to other injuries, the "a risk becomes a guarantee if you do it enough" logic probably applies to serious injuries in other sports, too, to say nothing of activities like drinking or smoking.