Could you summarize this article and tell me how Cinco de Mayo became a celebrated event in America?

Cinco de Mayo (Spanish for the Fifth of May) began with a proclamation from President Benito Juarez of Mexico, but ever since it's been a mostly American holiday. How did a Mexican battle turn into an American celebration? To answer that, we need to start at the beginning.
The History
In the 1860s, the Second Empire of France under Napoleon III waged war against Mexico, with the intention of deposing the liberal government of President Benito Jurez. Napoleon wanted to create a new empire in Mexico that would ensure French access to the wealth of Latin America. The timing of the American Civil War also meant that the United States would be unable to enforce its Monroe Doctrine in support of the Mexican army.
The Battle of Puebla, fought on May 5, 1862, was a more symbolic victory than a strategic one. A small battalion of Mexican troops under General Ignacio Zaragoza defeated a much larger and better-equipped French army at the city of Puebla. The victory delayed French forces' advancement in the country, and provided a major morale boost for pro-Republic forces. The French troops were successful in conquering the capital of Mexico City and establishing a monarchy, but the Republicans rallied and regained control of Mexico by 1867.
President Juarez declared that May 5 be a holiday to commemorate the valiant efforts of Puebla's defenders. Its acknowledgement in Mexico is minor and fairly regional, with the most recognition around Puebla. This should not be mistaken with Mexican Independence Day. Mexico's independence day celebrates independence from Spain on September 16 and is one of the biggest Mexican holidays.
The Battle of Puebla occurred on May 5th, 1862, when Mexico triumphed over a larger and better-equipped French army. President Juarez declared May 5th as a holiday to recognize Puebla's defenders, but it is a minor occasion in Mexico compared to the larger celebration of Mexican Independence Day on September 16th.