Why don't white girls have a backbone?

i was in the store the other day and this white chick was with this black dude. he was disrespecting her in everyway possible and she just took it. She didn't do anything but stand there and let him talk to her like that. He didn't want to help her carry the groceries and as a matter of fact left out of the store with an attitude. Now if it was me i would have smacked him in his face, am i wrong? Do white girls usually let men just walk all over them like this?