Yeah, totally and your chums from private school, who visit the opera every week curse, swear, cause trouble and shout abuse at folk who like the opposing equivalent of opera? A town nearby even vandalised the local Asda so much, they were forced to change the logo colours from green to blue. That would totally happen with your opera comparison, totally.
I think I was being completely sarcastic and making a ridiculous generalisation to match your ridiculous generalisation.
Its quite simple, something HAS to be the most popular thing, thats just how life is, if football had never been invented, badmington may have become the single most watched and played sport ever. In being the most played and watched sport, you'd have a huge amount of people getting together to watch matches.
Its scientific FACT that behaviour changes when you're out in a group, the bigger the group gets, generally speaking the dumber they act and the more accepting of poor behaviour they become.
The fact is football simply became the most popular sport, by a massive massive margin over everything else. That means more people play it, more people watch it, more people get together in pubs to watch it, more people get together in stadiums to watch it.
Take any gang in the country and its likely they'll have a majority of them support one team, because thats how life works, we organise ourselves into groups of people who like the same thing. If it wasn't football, it would be rugby, or cricket, or fishing, it doesn't matter. The bigger something is the more likely kids are to get drawn into watching/playing/enjoying/supporting it through life, this is natural, its got smeg all to do with football.
If Opera was the largest form of entertainment in this country and millions of people watched it every week, encompassing a larger percentage of the population would also mean more criminals and thugs would get into opera.
The things you are talking about are just fundamental parts of human beings, grouping together, disliking other groups of people, finding things in common you have the other lot don't and hating them for it. If it wasn't football it WOULD be something else.
With the Celtic/Rangers divide its got smeg all to do with football, theres just two groups of people who ages ago decided to hate each other, then they got into football and both sides chose a football side to support, and now they make it about football.