My friend is dating her friends ex

I have a friend named naomi that is very simple, she went out with her friends ex-boyfriend and the only reason why he broke up with her friend to go with naomi was because he knew naomi was very easy, everybody at school is mad at her and cursing ehr out for doing that to someone she calls her best friend, and naomi thinks she did nothing wrong, I tried telling her but she wouldnt listen, my question is what do you think of naomi, and what should I do???

I think that naomi knows she has done something wrong but denies it anyway. Really because it was he 'best' friends ex she shouldnt have gone out with him in the first place. friends shouldnt do that to friends.

I dont think she sounds as if she's a bad person maybe a bit of a bad friend for going out with her best friends ex. If it was her 'best' friend breaking up with the boy then that would have been a bit better but because the boy dumped her it isnt.