Usually when black battle rappers go for attacking their opponents race it's weak, everyone knows there can be no real retort for it. Classic example would be serious jones vs Jin, I mean Jin did get slaughtered but it was because of jones using the advantage of being black, you can't really say jones is better than Jin off the strength of that battle because It was essentially Brady throwing the deflated ball. the difference here would be that the brother was already winning before he went there.