This is reaching new levels of bizarre.
To start with, Cinco de Mayo is as contrived a holiday as is Kwanzaa. In Mexico, it is celebrated almost exclusively in a single state, Puebla, which has no border with the US and is in south-central Mexico. There it is called El Día de la Batalla de Puebla (English: The Day of the Battle of Puebla).
So, in effect, instead of honoring Hispanics of Mexican descent with a *real* Mexican national holiday, especially Revolution Day, Mexico’s *big* national holiday, which is celebrated annually in Mexico on the third Monday of November, marking the start of what became the Mexican Revolution, some people in the US created a *bogus* holiday for ethnic Mexicans to celebrate.
So what is the court doing?
It is saying that Americans cannot celebrate their country on the same day that Mexican-Americans are told they should celebrate a holiday almost exclusively celebrated in the US that has almost no relevance to their ethnic history.
WTF? This is like saying that Americans cannot celebrate their country on Saint Patrick’s Day, for fear of offending Irish Americans; or during Octoberfest, for fear of offending German Americans.
Or Easter, perhaps, for fear of offending rabbits. Arbor Day, for fear of offending trees.
Or, now that I think about it, during Kwanzaa, for fear of offending west Africans. Though right now it might be called “Ebola-Day”.
My Hispanic friends agree with you on the meaning of Cinco De Mayo. It is in no way equivalent to the Fourth of July. It celebrates the battle you described.
Kwanza was started by a Black nationalist (Ron Karenga?) and is completely made up. Sort of like an early version of the next AA national anthem, “Hands up. Don’t shoot!”