Pardon me for stepping into your forum.
Wasn't there a post a while back referring to some grocery stores that had sales in honor of Black History Month? I think it was related to people being offended at the products that were featured which have stereotypical connotations (such as fried chicken...). It seems like that would be akin to the Mexican food being on sale???
As far as people of all ethnicities celebrating Cinco de Mayo, here in Texas the celebrating is pretty widespread. And in June, Galveston is all about Juneteenth. I guess it just depends on the geography and culture.
dzsaigirl