We can all remember being picked for the team, all lined up 
against the wall, the best two players facing the rest. And then the dreaded selection, as the captains choose players in order of skill and popularity until the unwanted player is left standing against the wall (and he will be made to go in goal). Nowadays I suppose this wouldn’t be allowed in school because it would traumatise the less able.
However this scene will be played out in various forms as these children go through life, being chosen from a line-up of university hopefuls, jobs hopefuls, dating hopefuls and more. To shield children from the highs of success and the lows of failure in competitive life is to fail to prepare them properly.
Imagine if every day you were made to go out on the streets and advertise your services to passers by in the hope of getting a day’s work. Imagine those around you being picked and you left unchosen. Imagine you are older than the rest, sitting next to your beaten up bicycle having to compete for work with the young muscular men on their mopeds.
So in order to be able to take the knocks that await all but the beautiful, talented and popular, let the picking of the football team be the training ground for real life.