The link I provided above shows people many years ago wearing suits to sporting events and being well behaved. It suggests that the downfall of society is what leads to people doing stupid stuff.
In the past families stayed together, now most people are divorced. And people don't go to church and believe in God like they used to. So the only place they find they belong is with other like minded sports fans. But there's no moral basis for the group like there would be in a family or church.
I never really considered this before, but the biggest downfall not only for sports, but life in general is the disappearing family and God.