Because it was an accident that was almost certainly not her fault and yet she has to live with it the rest of her life.  What kind of callous person wants to then rub her face in it is the more troubling.  I mean what kind of person does that?  What type of character do they have?  Not much quite frankly; even the sister forgave her and recognized she was not speeding or on the phone and the sister stepped out when she should not have...