I would break the topic down into 3 groups: 1) People who play football through high school
2) People who play football through college
3) People who play football professionally
I would measure the health outcomes of these three groups against the health outcomes for the population in general. I think this information is much more valuable to football players in particular and the general populace (eg. parents who are thinking about signing their kids up for little league football) than the hearsay, single person point of views that pervade the airwaves and newspapers.
For instance, if I had children (I do not), and was thinking about signing them up for little league football, I would be much more worried if Group #1 lives 5 years less than average or has 2X the chance of developing such and such conditions than I would be about one particular incident, which might not be reflective of the norm. Ditto for the young men (and sometimes women) who are thinking about participating in high school, college, or professional football leagues.
As for the NFL, I think that it has an obligation to undertake these studies (at the professional level) if they have not been performed already. If the NFL is reticent, then the NFLPA has an obligation to its player members to undertake these studies. These organizations have a further obligation of giving the results to NFL prospects (and current players). In other words, the NFLPA could say, "Okay, if you play football, you are 2X as likely to suffer from this disease, and 3X as likely to get this one, etc. Oh, and by the way, some people might try to injure you on purpose."
Now of course, the company (or in this case the NFL), does have some obligation to look out for its employees. Soldiers don't go into battle without helmets; workers don't go into hazardous areas without HAZMAT suits, and players should not get on the field unless they possess the latest in personal safety equipment. Nonetheless, at some point, it is up to the player (or his/her parent) to make the final decision; it is up to them to decide if the risk is worth the reward.
As an aside, I apologize if this post meanders a bit. I wanted to posit my true feelings on the issue. So, what i have written comes off the top of my head; it is a reaction to what I've been hearing and reading.
Update: Thanks to Jax's blog, Raviolis & Waterworks, for pointing to this Fox Sports article by Alex Marvez discussing a NIOSH study of NFL players which shows that, on average, they live longer...The study might not cover all the bases, ie. compare players to other groups regarding non-life threatening diseases like arthritis; however, those studies are likely out there as well.
1st photo courtesy of Stephen Horncastle (photographer/owner) via Wikimedia Commons. It is from geograph.org.uk and part of the public domain via a Creative Commons Attribution-Share Alike 2.0 license.
(photographer/owner) via Wikimedia Commons. The image shows Roger Goodell at the 2009 NFL Draft. Ms. O'Leary has authorized re-use of the photo via a Creative Commons Attribution 2.0 Generic license.