For whatever reason, CNBC keeps lining up challengers to take on its Chicago Mercantile Exchange floor reporter Rick Santelli over his self-reliance, pro-taxpayer persona - whether it's Steve Liesman, Arianna Huffington or this time, Keith Boykin - editor of The Daily Voice, a CNBC contributor and a BET TV host. ON CNBC's May 7 "The Call," Santelli took on Boykin in the program's "The Call of the Wild" segment. Boykin was armed with the usual anti-George W. Bush talking points. "Look what he inherited first of all," Boykin said. "He didn't inherit anything," Santelli said. "He ran for office, it...