How is Stacey's reaction to Mr. Barnett's insult in the store different than Cassie's

Stacey begins to drag her out of the store, and Mr. Barnett tells him to "make sure she don't come back till yo' mammy teach her what she is." Cassie is mortified by what happened but Stacy is more practical about it. I'm sure he is hurt too but he sees the impending seriousness of the situation for his family.