I would say that the NBA is explicitly not about giving everyone the same chance. Not everything has to be about giving everyone the same chance. A totally equitable NBA would probably be less entertaining to watch.
But that doesn't mean we can say that standardized testing gives everyone the same chance either...
NBA gives everyone the same chance to get it, just you have to be good at basketball.
If the circumstances of your childhood made it so that you are shit at basketball but hey you were the top performer in your group of terrible players, the NBA is not going to pretend like you are good enough or grade you on a curve because of your circumstances.
Because if the NBA does that, well,
you will get crappy players in the NBA. And can you then say that the NBA gives everyone the same chance to get in anymore. Just move to a neighborhood where everyone is shit at basketball and you suddenly have a much higher chance at getting into the NBA? That’s a much more unfair system than a standardized measure.
But that doesn't mean we can say that standardized testing gives everyone the same chance either...