I would say the people of Mexico may be overly prideful of their futbol. But seriously guys, why wouldn't they be proud?
There isn't a lot of things to look forward to. You mentioned a flag only visible from the US border. I bet it's sort of a way of saying "Here's our turf." You cannot blame them for hopping a border to come over here to make ten times the amount of money to send back home. Most of those people, the immigrants, are good family men.
They also, for the most part, value those things in appropriate order: God, family, job, and everything else. For a lot that's soccer. They most certainly aren't a world's power.
But try to look at it from their perspective: What a great victory to beat the juggernaut United States. A few have mentioned their arrogance. As most of you know and may possibly be yourselves, Americans aren't always kind and have quite a few preconcieved notions about the people of Mexico. Can you imagine how arrogant we must seem?
The problems Mexico has on the north border are ALL problems, we, the US have created. Cheap work without having to pay benefits by ranchers, farmers, and small business owners continues to stimulate the people to come over. Free medical treatments that are near-logrithmically more advanced than most of their treatment centers, and drug dependence are a few crutches they have to over come.
They are economically depressed. Sure some thank us. But most despise us for what we've created. I mean how can we hate them for what we've made them? In reciprocity, how can they hate us for what we've done? It's a lot easier for them to generate the hatred in that circumstance.
So when they beat a rich and flourishing nation, in their eyes, they've beaten Goliath. Or better yet, they've beaten a country whose punk card they've had before in soccer, but have lost recently. As you mentioned, we've sent them home packing. But they beat us 5-0 in Mexico about half a year ago, and they were ecstatic. They guage their run in competition by us. And for the most part, it's friendly competition guys... And apparently, this year, we are a pretty good guage. They've made it to the knockouts, and if they beat Argentina, they've got Germany or England. Tough luck there.
But I respect your opinions. I'm certain life in SoCal is different than life in New Mex. It's plausible the people there are different than here, from both sides of the border. Just as people in New York are different than those from Tennessee.