Many 'Mercans hate soccer so much and resent its "intrusion" into American culture and consciousness that they will always want an American team to lose.
A good example of this was with the men's failure at T&T this last WC qualifying cycle. The very night of that loss, during the CB soccer head's threads of despair, more than one CB soccer "outsider" intruded into the discussion to rub it in. All because of their 'Mercan resentment of the Game in their USA.