Couldn't agree more OP. I think there's something unhealthy about grown people having so much invested in a sporting event that they're in performative ecstasies and agonies. Sure, people are happy when their team wins and disappointed when they lose - the performative bit is the sheep-like moves:
Our goal = throw beer in air, grab nearest person and jig around
Their goal = hands on head, stare ahead bleakly, or look around disbelievingly
Win match = lose shit entirely
Lose match = be inconsolable, cry, say 'gutted' a lot.
It's cringe in adults. And when children pick up that this is how they're supposed to react, yeah, creepy's the right word as far as I'm concerned.
Personally I wouldn't take my kid to any event where there's going to be armed police and drunk men shouting, but I get that lots of people see it differently. But it's the weird emotional vibe - that's increased since men learnt it's bad to hide their emotions - that I think is wrong for kids.
Younger ones can't deal with their own big emotions, let alone those of a crowd of adults proud to be barely in control of themselves. Of course the kids will copy the adults to fit in, and look as if they're fine with it. But I do wonder what repeated exposure to this behaviour could be doing to them pyschologically.