The demented and idiotic acts of soccer fans around the world have been well documented, and subsequently, the line between soccer fan and soccer lunatic has become more and more fuzzy. At the same time, the line between proper and improper is almost invisible.

And in Team USA’s 2-1 loss to Mexico last weekend, that line was crossed. Then it was crushed. Then it was spat on.

With the home team up 2-0, USA scored a goal in the 59th minute, prompting some of the 100,000-plus in attendance to chant, “Osama! Osama!”

It’s an act inconceivable to American sports fans.

It’s wrong, obviously. But it’s more sad than anything.

Sad because sports are supposed to be fun. The game is supposed to entertain; it’s meant to be enjoyed. Then, when something like this happens, sports become disturbing and sad.

It becomes news, not sports.

And people like those who chanted “Osama! Osama!” ruin some of the things sports are supposed to encompass: camaraderie, goodwill and fun.

Surely there is not rationale for that behavior. Just like there wasn’t any rationale for the behavior of a Mexico player who, following his team’s loss to USA in the 2002 World Cup, told USA star Landon Donovan that he would, “find your mother and kill her.”

Mexico fans apparently had their reason for behaving in such a sick manner — their national pride had apparently been dented by that 2-0 loss to USA in the 2002 World Cup, which knocked Mexico out of the tournament.

And since they couldn’t directly take their frustrations out on the players, they chose to chant “Osama! Osama!” and pelt the small group of USA fans in attendance with water bottles, coins and other throwable items.

Maybe “sport” translated into “dysfunction” for these fans, who had earlier booed and whistled during USA’s national anthem.

In 1985, a vicious earthquake struck Mexico City. More than 30,000 people died, and it is considered to be the most tragic moment in recent Mexican history.

And when the two teams meet again Sept. 3 in Columbus, Ohio, it’s a safe bet there will be no mention of an earthquake.