Russell Crowe has a long history of misbehavior. Several years ago he faced quite a bit of criticism for attacking a hotel employee over wanting to make a phone call. He is a bit of a loose cannon, and it is completely believable that he would make racial slurs. People allow him to get away with too much just because he is a celebrity.
Women don't usually lie about things like this because it is very hard for them. They are often questioned and called liars for what they say. When it is about a beloved famous person, it is even harder for them to come forward. Clearly he is much worse that he seems.
No, Azealia Banks's claims are not a true concern due to her previous attempts at character assassination. She is a celebrity attempting to stay relevant by any means necessary. Unfortunately, she is trying to defame Russell Crowe and other celebrities such as Iggy Azealia in the process. If her only claim to fame is that someone called her a bad word, then she should be ignored.
She is a complete liar. She is always ranting and raving about something or other in order to get attention for herself and her nonexistent rap career. She has seen an opportunity here with Russell and taken advantage of the fact he has a history of violence with paparazzi and has gone with it. I hope he countersues her and takes her for all she's got. Maybe then we finally won't have to hear about her anymore. She is nasty.