These days, television regularly airs commercials that show Americans of different races and ethnicities interacting in integrated schools, country clubs, workplaces and homes, bonded by their love of the products they consume. For instance, the latest spot from ETrade stars a 9-month-old white boy, and his newest buddy - a black infant. "Multiculti" ads recognize a new cultural mainstream that prizes diversity, a recognition that we are fast approaching a day when the predominant hue in America will no longer be white. But some critics wonder if depicting America as a racial nirvana may have an unintended downside …