Every year, we read articles revealing the true origins of Cinco de Mayo. Nope, not Mexican Independence Day, which happens Sept. 16. Cinco de Mayo commemorates a minor battle in the state of Puebla in 1862 where an army of mostly Mexican Indians beat Napoleon III’s French troops. The holiday isn’t celebrated widely in Mexico. It only became popular in the U.S. during the 1970s when Chicano activists grasped the David-and-Goliath symbolism and gave the holiday a boost, recognizing a parallel to their own cause….