Because the WNBA, like every professional league, makes every effort to keep their best players playing.
Do you want the rule book followed to it's exact wording and a foul called on CC every time she pushes off? Of course not, no one does...fans want the best players playing as much as possible. CC pushed a player into the basket stanchion last night away from the play, which would have been an easy flagrant if they wanted to, but nothing was called and nothing came of it...which is perfectly fine.
Why do you think it is that Fever/CC fans think Aja gets a special whistle and just as many Aces/Wilson fans think CC gets a special whistle?
Because they BOTH get a special whistle at times...like just about every great player before them.