Cinco de Mayo is not even a holiday in most of Mexico. It is just a reason for people in the U.S. to drink Tequila and Mexican beer. Not that there is anything wrong with that.

May 5th is the day the Mexicans defeated the French under Napolean III at the Battle of Puebla. It is mostly a local Holiday down there.
I cannot believe we would send kids home for wearing the flag or it's colors. I don't care if it is "shennanigans". I agree and call it BS too.