Is it rude to tell a black person that they aren't your brotha/sista?

I've had black friends come up to me on the streets and call me brotha and stuff and the friends im with are white and not into that. its embarrasing. i no they dont mean to be like that, but why do they have to act all ghetto and weird? how do i tell them that they are embarrasing me in front of my friends that arent hip to that culture? im not ashamed to be black, but i dont like that ghetto culture and i want to get away from it.