As part of this thought exercise, let's take as a given that CTE doesn't exist and brain injuries are unimportant.
After that, let's look at the prevalence of diabetes, heart disease, and other long-term degenerative diseases in the NFL player population.
Then, let's look at the shortened earning potential of the NFL player. Yes, for a year, maybe more, they are highly paid but lifetime earnings might not be what you'd expect. How do the stresses of many men who leave the NFL with no skills and often an abandoned college degree affect them and their families?
Next, let's consider the lifestyle the NFL envisions for its fans. Spending at least a full day each week sitting and eating unhealthy food while consuming alcohol. Spend the rest of the week gambling on the outcomes of the games (or individual players). Much of the time, this fandom is done as a family leading to impacts on children in the home. There's a societal health impact here.
The list goes on if we follow this thinking. So, if we go back and remove our given, we end up with a spectacle that unduly endangers its participants, encourages unhealthy behavior in its fans, and indoctrinates our youth to be accepting of all the above. Meanwhile, a very few wealthy families get even wealthier on the backs of all that.