Personally my objection to the idea of tailgate parties is why on earth would I want to stand outside in the cold and rain eating burnt meat from the back of someones car
You wouldn't. And unfortunately, if you tried to tailgate in the UK, that's exactly what would happen. Because they'd be doing it
wrong.The wrong meat, the wrong charcoal, the wrong equipment, the wrong space, and also, it occurred to me this morning, no Red Solo Cups. And probably the wrong beer, too.
As for attitudes, I stand by my original comment. People might get excited and enthused and overjoyed about the game itself, or about the prospect of battering the other fans before/during/after, but I don't think it's natural for people here to simply enjoy the day out itself, and the company of crowds of strangers. Y'all barely make eye contact in public, if you can help it. You simply couldn't ever replicate the atmosphere.
And that's ok. As you say, people in different countries do different things.