The Irish didn’t celebrate St. Patrick’s day in the 70’s but had to relent due to the tourists who constantly asked where the parades/celebrations were. I know it annoyed the guy I was working with at the time but I added it to the list of things he didn’t like about America.
Yeah, in Ireland it was a solemn day of church going and prayer. Americans aren’t really into that kind of holiday though, we like to drink, eat, dress like idiots, and just generally have fun. In the parts of Mexico that actually care about Cinco De Mayo it’s a fun holiday, but it’s very regional. We have a lot of those 1 region holidays here too, mostly revolving around the Revolution, or the Civil War, and some day some beer company will figure out how to hook a marketing campaign on them and they’ll become national.