creation of a holiday.

Cinco de Mayo isn't celebrated in Mexico, or at least not like it is in the US.

Christmas--well, it is extremely doubtful that Jesus was born on December 25, when the shepherds would most certainly NOT have been out in the fields. The most persuasive argument I've seen says probably late fall, 2 BCE.

Memorial Day was probably celebrated on many different days in many different places before the Uniform Monday Holiday Act of 1971, so I was a junior in high school when THAT sacred holiday changed to the last Monday in May so as to facilitate that most wondrous of modern calendar innovations, the "three day weekend." (yes, anybody born after about 1955, we didn't use to have those. I remember being at Little League practice in about 1963 and somebody having brought, on a regular weekday when our dads were all at work, a radio so that we could hear the Indy 500, which at that time took place on May 31, period.)

While the Juneteenth story (at least it's true, as in: it actually happened, if limited in impact) probably only affected a few slaves in Texas, who am I to tell descendants of slaves anywhere when they should celebrate the date of emancipation in the slave states? Seems to me that's up to them.