While it may be all in good fun, Cinco de Mayo is an appropriation of Mexican culture that some may find offensive. It involves playing at being Latino in a way that is disrespectful to those who have actually lived their life as a Mexican, and discounts their experiences and struggles.
Yes, the U.S. can be pretty racist when celebrating Cinco de Mayo. Most celebrations do not recall the history of the day, and know nothing about why it's celebrated. Instead, it's an excuse to wear huge sombreros and eat Americanized Mexican food. This holiday is not largely celebrated in Mexico because it was brought to prominence by a dictator who was later deposed through the Mexican Revolution. Celebrations of this holiday in America is often cultural appropriation, as well as inconsiderate and ethnically demeaning.
Very few people actually know the history of the Cinco de Mayo. Instead of celebrating culture and a victory in time of conflict, most people use it as a day to eat Mexican food and drink alcohol. Celebrating a day in this manner seems inherently disrespectful to a racial subset of America.
I do not believe that to be true about Cinco de Mayo. This holiday is a Hispanic holiday so I do not understand how it can the celebration of it has racist undertones. I just think for people who are not Hispanic it's just another reason to celebrate and get drunk but racist no.
Honestly, we play Mulan and Kung-Fu Panda for Chinese New Year and only remember black history for the shortest month of the year. We drink gallons of green beer while watching "The Luck of The Irish" and stock up on Nachos for Cinco de Mayo. To be quite honest racism implies a degree of malice that simply isn't present here.
It's like watching Japanese anime if you happen to be black - sometimes all you can do is shake your head. Because they aren't generally trying to be actively racist... It's just a lot of really, really unfortunate implications. You know like that commercial from China with the little black girl and the KFC chicken. No harm was meant, but it just looked bad.
So yeah... Maybe back off a little bit? Unless you're a non-American Hispanic in which case I'd love to hear your thoughts on this.