Lotsa wrong answers here!
OK- Cinco De Mayo is a proper celebration in Texas because the leader of the Mexican defense against France at the battle of Puebla, was General Ignacio Zaragoza de Seguin . A NATIVE TEXAN. Just as G. Washington's birthday is celebrated on both sides of the border (more in Mexico than in Texas) as being the first leader to throw off European dominance in the new world. Similarly, Bolivar's exploits are celebrated beyond Columbia, Peru, and Bolivia.
Cinco De Mayo recognizes that a NATIVE TEXAN fought bravely and helped to destroy French colonial designs in 1862 in the new world. Hence- Cinco De Mayo, is a small celebration in and around Puebla, Mexico and La Bahia, Texas (Zargoza's hometown).
Because Corona, Tecate, and other beers are imported through Gambrinus Inc. in San Antonio, TEXAS, they seized upon an opportunity to take a small state festival and turn it into a grand marketing scheme. Now Americans go crazy over this small holiday just like St. Pats day, and they drink Mexican Beer rather than Guiness.
The real Mexican Holiday is deiz y Seis or 16 September day when they won their revolution.
We aren't celebrating a Mexican Holiday so much as a Texan one.