I take it you are talking about American football. it just happens to be part of the culture. Like in the south people are obsessed with sweet tea and NASCAR, and out west everybody is a cattle rancher (don't mind my stereotypes). but football is a multi billion dollar industry that is endorsed by almost everything, so of course people going to like it. Plus to some people they like the sound of people just beating the junk out of each other, some people like it for the commercials, and some people like it just because its American
men like sports, it gives them sense of completion
Sadly, it happens whether its football, rugby, AFL or american football. I do sympathise as the season goes from August to May. Why are they so obsessed? Tribalism comes into it. Familt may have been supporters and he's carrying on the tradition. Tell him to lay off the twitter while you're around or to restrict it to game time only. JT, as this is the Australian Football: Other Football I doubt the questioner is talking about gridiron.