AROUND 8 A.M. on a cool, clear Monday in mid-November, James Cox Chambers Jr. is in Gresham Park, in southeast Atlanta, bouncing on the balls of his feet, shadowboxing the air in front of him. Dressed in a black hoodie with a Palestinian flag on it, black sweatpants, black New Balances, black-and-red work gloves, a white-and-black keffiyeh, with a balaclava ski mask perched on his head, Chambers is surrounded by a growing crowd. But at that moment, focused on his warmup routine, he looks very much alone.
Paige Belanger joins him on the grass, and for a few minutes, they practice arm drags, a move Chambers picked up in mixed-martial-arts training. Belanger is a member of the Babochki Collective, a group Chambers recently formed to help turn the vast…