It's not racist but the fact that we find the need to specify that it was a black man or a white man or an immigrant doing a specific crime only leads to a further divide. This was one man commitng a crime. Being black in this context is not important which i believe is what Juan Cabrera was trying to specify. It explains where the man is from and that he is an immigrant and that can imply that this is what most blacks and other coloured people are doing and that can make us biased.