This Cubs fan went to a Cubs-Cards game c. 2002 wearing Cubs gear. While waiting for the train back to where I’d parked, there was a drunken Cards fan across the tracks hurling invectives at me. Had we not been separated by about 30 feet of electrified, busy light-rail track, I genuinely think he might have tried to assault me.
I think that a lot of the time in the rest of the world, fanbases can be synonymous with other societal divisions- e.g. Rangers supporters were typically Protestant, while Celtic supporters were typically Catholic. Or some clubs may be tied with specific neighborhoods/blue collar populations. Or even more weirdly, politically affiliated, like the left-wing support of Roma, and right-wing of Lazio.
For whatever reason, US sports teams don’t tend to get the sort of stark demographic lines in fan bases that soccer clubs tend to get. Even where there is a geographic distinction like between the Chicago baseball teams, they play in different leagues. Otherwise, it’s kind of a “pick the team you like” sort of deal- there aren’t defined areas where Mets fans live, versus Yankees fans. Or Jets/Giants. Or Chargers/Rams, etc…
I kind of wonder if it’s due to the historical roots of a lot of soccer teams as having grown out of neighborhoods, rather than being “imposed” from above by a rich owner.
To a certain extent, there is some stereotyping around Cubs fans and White Sox fans in Chicago, which is in part a reflection of the North Side versus the South Side. And, even though the two teams didn’t play against each other for many years (until interleague play was introduced), there was absolutely still a rivalry between the two fan bases.
I see Cubs fans stereotyped as either (a) rich Northside yuppie-types, or (b) drunk partying twenty-somethings, who treat going to Cubs games as big parties. Meanwhile, Sox fans are stereotyped as blue-collar South Siders, and louder and brasher than Cubs fans.
Those stereotypes aren’t particularly fair, but they do seem to endure, in my experience.
Edit: a couple of articles on these stereotypes, as cites that it’s just not me. 
All I was trying to get at is that sometimes in Europe, the soccer fandom is more or less an excuse to wreak violence on another group- another neighborhood, another socioeconomic strata, another ethnicity, etc…
Cubs/Sox rivalry doesn’t have that same underlying animosity from what I can tell, or maybe that sort of thing isn’t as hostile in Chicago as it is elsewhere.
Fair enough; you’re correct in that it’s essentially unheard of for Sox fans to go looking to pick a fight with Cubs fans, or vice-versa.
The best-known bit of violence related to Chicago baseball fans in recent years was 20 years ago, when a drunk father-and-son ran onto the field at a Sox game, and attacked the Kansas City Royals’ first base coach, for no apparent reason.
Yeah, that sort of sports violence is just not a thing in American culture. I mean, I’ve been to a few big rivalry college football games (Texas A&M/University of Texas) and seen a LOT on TV (like the Oklahoma/University of Texas game) , and it’s not at all uncommon for fans from both teams to be interspersed among each other. They get ribbed and teased, but there’s no hostility. If nothing else, we all acknowledge that we’re from the same state and that it’s just a football game.
I’ve seen hostility and plenty of fights at Met-Yankee games but they don’t get so big that security can’t end them.
Drunken yelling is one thing. There’s 20 or so Cubs/Cards games a year with a sizable number of fans from both teams attending. But it’s not like there’s some epidemic of assaults after the games.
I think fights at American sporting events tend to be more “You spilled my beer!” and not “There’s a Mets fan! Get him!” Two drunks fighting over a spilled beer isn’t likely to draw in a bunch of bystanders, the way identity based violence does.
No, it’s not quite “there’s a Met fan , get him” but neither is it over accidentally spilled beer. It absolutely starts with something said about one team or its fans by the other team’s fans and while the fights don’t get so big security can’t end them , they often involve more than two people.They are usually drunk, though.
The intensity of Europeans is just a lot higher. Look at this video of American vs European basketball fans. The Europeans are far wilder - and basketball isn’t even Europe’s main sport!
Well yeah, a lot of teams were created by people with some affinity. Sometimes it was just people in the same neighborhood wanted to start a team. And due to the promotion/relegation system, it isn’t rare for multiple teams from the same city to be playing each other constantly. And people will flock to one team or another for various reasons - and yes, sometimes that can be for political or religious reasons. Similar to Catholics supporting Notre Dame in college football, it was a way to feel part of a community.
I get the impression that the spectators at soccer games have a noticeably higher concentration of adult males than other events. Meaning, most of the men in attendance don’t have the civilizing influence of their womenfolk or have need to protect their children.
10x only? No, you are way off. Look, that is just the players. The fans have killed each other more than once. They call this atmosphere. It is beyond crazy.
Low class too. Lumpenproletarians who are confused about the real enemy.
I heard that at the Indonesian stadium that had a mass-casualty event this weekend, the place had something like 38,000 seats, and they sold about 44,000 tickets.
Because Indonesia is mostly Muslim, I wouldn’t consider alcohol to be as big of a catalyst as it might have been elsewhere, but I did hear that the police also shot off tear gas when things started going sideways.
Selling more tickets than seats is a sure way to produce a riot. As is having tickets that aren’t copy- and counterfeit-proof enough to prevent bad actors from printing and selling another 20K tickets for good measure.
Hell, go back to the racing teams in Constantinople of the 500’s.
Leaving out the Indonesia situation, are children not generally brought to football games in Europe? Seems to me that, putting aside the potential for violence, a football game would be a great family outing. Do European children not generally go to football games until they’re old enough to defend themselves?
What industry are you in again? 
I’d guess so, yes.