The current jury system is kinda biased in a class? or something way.
Low paying, part time, or new jobs don't pay for jury duty, which means even if they maybe can't fire you (they sure aren't going to promote you!), with the nothing that is paid for jury duty, low income types need to avoid it at any cost.
Then, you can be excluded on the basis of prejudicial feelings towards the defendant or witnesses - like cops or drug dealers - if you personally hate drug dealers, or hate cops, you won't be on the trial of a drug dealer. And, of course, those living in impoverished neighborhoods are more likely to have had either negative contact with a drug dealer, or negative contact with a cop (since druggies don't like the lawabiding in their neighborhoods, and criminals get along fine with the druggies, but don't like cops).
It's people with somewhat easier lives, with a job they are fairly comfortable in, or a retirement with enough spare money to afford jury duty (at least when I did it, the parking fee was higher than the jury duty pay!) that go on juries, that don't fight it too hard. And that does put a bias that has an effect of reducing or eliminating the number of black people on a jury.
Then, the defense attorney no doubt knew who he didn't want, and tilted the jury even further white.