As a huge fan of both this is what I gather.
Monica is ghetto as Dallas said. Monica did not understand a lot of things in the business, being protected by Dallas and not living in LA as it was said in the video. Monica took Brandy hand in her face as disrespect when it was really just acting. Brandy was not only bigger than Monica and more successful but she made it be known. Many people have spoken about Brandy's attitude back in these days, and I am sure she displayed this with Monica. Monica handled the situation wrong, very wrong.
I think that they are both slightly jealous of each other. Monica's career route was a very easy one, one contract, total control, and a lot of freedom. Brandy never had this, she was picked a part and scrutinized. I am sure Monica could have been jealous of Brandy winning everything, that has to be hard to watch. Monica is very hood but she can also be very Hollywood, she has been molded to be. We all know she attaches fake titles to people, everyone is her BFF, auntie, cousin or God Mother. I think her personality is a bit much and is not for everyone. But, Brandy clearly has an issue with dealing with situations head one, she subliminal and shady, and avoids direct confrontation. While, Monica probably shouldn't have said what she said in the interview, I don't think there was any ill intent. Brandy being Brandy, doesn't talk about it, doesn't say anything, probably bottled up her feelings and ran away with it. Monica appears to have a problem with her mouth and hands apparently, but Brandy's life has show that she has a problem with conflict resolution and how she feels when someone does her wrong.
I wish that they could just talk it out and move along for good. Now would be a good time to discuss how they want to address what happened together and close that chapter.