I lol at all the people who get completely smashed on St. Patricks day who aren't even Irish. Lucky for me though I am of Irish decendancy so I am allowed to. :P
In all fairness, by many with no connection to Ireland, it is just an excuse to get pissed.
Which is why many people, including those who on any other day of the year would curse an Irishman, all celebrate St. Patricks day.
If most non-well-known religious holidays, such as days for Saints, made a tradition of drinking, they'd probably be very popular too.
People love to get pissed in the middle of the week.
It's celebrated Because St. Patrick was a good person, not because he was Irish.
Technically, it's partially because he was a good person, but mainly because he is the Patron Saint of the Irish.
Which is why it's traditional for the Irish to celebrate the day.
You wouldn't get lots of people celebrating every other Saint's Day in the world just because that Saint was a good person.
There are hundreds of Saints who are linked with just my local county. They're simply remembered in History books.