In 1862 during the French-Mexican war a poorly supplied and outnumbered Mexican army defeated the French who were attempting to capture the town of Puebla. This was a great moral victory for Mexico who was able to defend itself against the more powerful foreign nation.
In modern-day we celebrate this moral victory by drinking lots of alcohol and over eating in an ethically insensitive way. I am not of Mexican heritage, my families roots are from Guatemala. We do not however go on a bender on September 15th every year to celebrate the independence of Guatemala. I think the people who celebrate the most have no relation or care for the day, they just want a reason to drink more. I think that if we want to drink about something we need to find better days to do it on. How about October 10th, the day Jack Daniel died or even May 4th the day in 1964 when Bourbon was recognized by the US Congress as a distinctive product. At least when you drink on those days it makes a little more sense!