Because girls like that are ***** when it comes to men calling them out. She would have been even more likely to kick, slap, punch and scratch them in the knowledge that they'd be unlikely to retaliate and give her the punch that she'd have deserved.
She deserved the several slaps that she got - it was enough to teach her a lesson. They were just girly slaps anyway; I'm sure the tall black woman was capable of much more if she'd wanted.