I think if she caused offence she should have apologised and that be the end of it. She didn't and I support the BBC's decision.
BBC site said:Carol is mortified that anyone should take offence at a silly joke. She has summarily apologised.
I really need to find out who she was talking about. If he/she did indeed look like a golliwog then I don't see the problem. A note to all budding BBC employees though - don't think of using a simile to describe something in your interview - someone might find it offensive.