“Concussion” – starring Will Smith as Dr. Bennet Omalu, the forensic pathologist who blew the whistle on NFL head injuries and their relationship to chronic traumatic encephalopathy (CTE), a form of dementia – opens on Christmas Day and is already stirring the pot.

Some say it’s too easy on the NFL.

Others that the movie plays fast and loose with the events and exaggerates the relationship between football and poor health.

“Are we actually watching players kill themselves before our eyes?” Daniel Engber writes for Slate.

“No, not on average: A 2012 study of several thousand NFL retirees, conducted by researchers at the National Institute for Occupational Safety and Health, found that the former football players lived significantly longer than race- and age-matched controls.”

The same study, he writes, finds that ex-players are less likely to commit suicide than men of their age and race.

It doesn’t change the fact, however, Engber acknowledges, that “Omalu really did discover an unusual pathology in the brains of former NFL players, and the NFL’s corrupt administration really did attempt to discredit his research and then for half a decade ignored this important line of inquiry (only caving under congressional scrutiny).”

That’s right: Omalu made an important connection between concussions and subconcussive hits on the one hand and serious brain damage on the other – as demonstrated in the riveting PBS “Frontline” documentary “League of Denial,” which its flagship station Thirteen-WNET is repeating in advance of “Concussion’s” opening. (The documentary concludes at 10 p.m. Dec. 22. You can also find it here.)

If Omalu weren’t on to something, then why attempt to demonize him? It’s illustrative that Engber mentions smoking in his post. Only a fraction of smokers wind up dying of lung cancer, he writes, but smokers are 23 times more likely to get lung cancer than nonsmokers. That statistic, however, has been enough to galvanize the way we think about smoking. Yes, people still smoke. But there are few if any public places where you can do so, it’s hideously expensive and it’s no longer fashionable except perhaps among young people, unfortunately.

Could football be the new smoking? In “League of Denial,” Omalu says he was told he really didn’t understand the implications of what he was doing, that all it would take would be for 10 percent of mothers to turn against football and the sport would be finished.

All the more reason for the Omalus of the world to continue their line of questioning.