You never hear of someone throwing live animals off the St. Boniface tower during a celebration, or stampeding livestock past Heelan High School, at least not with the town's and church's approval. You don't hear us Protestants doing it either. Martin Luther did away with a lot of that Mardi Gras style revelry, leaving us with beer, potlucks and guilt. The most dangerous thing Protestants do is sample the macaroni salad that's been on the potluck table for two hours. What the goat-tossing tradition has to do with a martyred 1st century saint is not clear, except that St. Vincent is the patron saint of vintners and sailors.
Drunken sailors can think up about anything for fun.
I doubt that it was an accident. Unless the dairymaid is Quasimodo, nanny goats have no business in a church bell tower. I suspect the priest was getting tired of milking the stupid goat for the one poor person in town it could supply. Even more unlikely is that this is the only event in the thousand-year history of the village worth commemorating at the St. Vincent festival. I've lived in small towns with less history - just unlikely.