Is St. Patrick's Day for Irish people only?

Yes it is only for the Irish. 

I think that it is celebrated widely in the USA, but many "British" immigrants to the USA came from Ireland.

Nope ,for anyone

I'm not black. Can I celebrate Kwanzaa?

It's for anyone who wants to be "Irish" for a day. Here in Dallas, we had a parade on Greenville Avenue with 1,000 entries. There were floats, decorated cars, bands, dressed up pets, clowns, and just about anything else you could think of. It was a time for people to get drunk and stupid, and there were a lot of them. There was also an Irish Festival at a local park, and it was for owners of Irish Wolfhounds. Their owners didn't have to be Irish, but they all adopted Irish names for the day (e.g. O'Cardenas, McHernandez, etc.) All in good fun.

No. Americans just make a bigger deal out of the holiday than people in Ireland do.

i dont think so

In NYC it's seen as a Catholic Pride parade.

The event is to celebrate some fictional character called st. patrick who supposedly took snakes out of Ireland but in reality it would take centuries for a species to be wiped out of a country not by one person but by many nationwide. Anyone can celebrate this made up event.

Certainly not. Anyone can celebrate.