Brains are delicate things…
I guess play tips over into sport when there’s too much at stake (money, energy, self-esteem, vicarious living)
There is a long-standing elite suspicion of proles getting together in one spot and having fun together. A lot of leftist rhetoric also imports, usually unconsciously, old puritan notions in which passions are to be distrusted. That said; football, with its slowly changing cast of characters involved in artificial peaks and troughs of activity allowing those watching it to emote, performs the same function for men that soap operas do for women.
see also: fun versus entertainment.