As an Ulster Catholic, I would say anyone can essentially celebrate what they like. My family in Northern Ireland growing up never celebrated St Patrick's Day and still don't.
Patrick wasn't even Irish by any means and he was from Roman Britain which he referred to as "my country". Roman Britain is where he grew up and where his family lived, bit noone knows if that was in England, Scotland or Wales. You could mark St Patrick's Day from that angle anyway. The day IS supposed to be about Patrick's death.
Patrick's colour was always traditionally blue and not green. The green came in the late 19th Century in the United States parades in relation to independence. Hence, I wear blue on 17th March and make things that relates to Northern Ireland only.
But the earliest St Patrick's Day parades was organised by Irish Protestants in the US and these were NOT like the later green tinged stuff from the US. It didn’t even come to the Island of Ireland until 1931 and it wasn't until the 1980s when it became a big thing. Before that, it was a religious day for Catholics and Protestants.
Corned Beef and Cabbage isn't even an Irish thing. Irish immigrants took it from Jewish immigrants.
Patrick wasn't the first to bring Christianity to the island of Ireland either and there's no evidence he taught the Trinity via a three leaf clover.
Leprechauns were always male and not particularly good ones. They wear red jackets in the actual myths....not green ones. As mentioned before, green came in later for political reasons in the United States first before spreading over.