Maybe, just maybe...when you live in the low-to-middle portion of a third-world just-this-side-of-the-17th-century society, and you have nothing in your life that gives any indication that the future is ever going to get any better, then you live in the fantasy world that is presented to you, and it (in this case, "futebol") becomes your vicarious route to a sense of personal worth. Except that you have no control over it; when the team wins, you feel wonderful, and when the team loses, your "futebol" world is shattered.
In the US, you don't see it in sports so much, but you do see it in entertainment. (cf. "Whitney Houston," "Michael Jackson," "Elvis Presley," "Marilyn Monroe")
I do.
No doubt those are a great deal of the involved dynamics.
Nevertheless, loving when things go right and hating when things go wrong is animalistic. Human beings are here to rise above that, no matter what their conditions are. Collectivism under any excuse (i.e. even “fans”) urges “devo” behavior. This kind of thinking is unpopular, rejected, and mocked. Nevertheless, spiritual challenges don’t have to light up the sky in neon - simply not hating someone you would have loved a moment before because their best wasn’t good enough for world mastery is, I think, a reasonable start.
Unless we’re talking about Stevie Ray Vaughn. He’s different, and I don’t want to hear anyone dissing him.