In the justice league why is the green lantern ?

The John Stewart version of Green Lantern was used in the Justice League cartoons because one of the few potential Justice League members who wasn't white, and televison producers still think it is essential to have a minority character or two ("Super Friends" featured a few minority characters who were invented for the cartoon series, namely Apache Chief (Native American), El Dorado (Latino), Black Vulcan (African-American) and Super-Samuri (Japanese). Why a Black character is needed when the Justice League has a Martian character who is green puzzles me, but if I were Black I would probably appreciate that John Stewart was picked over any of the White Green Lantern (or any of the Alien Green Lanterns from distant worlds. I haven't seen a Justice League cartoon in almost a year, so I didn't know John Stewart wasn't on the show but I suspect he has been replaced by Hal Jordan, who was the silver age Green Lantern and the star of the various Green Lantern comic books for over three decades.