Back when the Irish were considered an 'other' and like vampiric monsters sucking all the jobs out of America, there was a period where they slowly started working as pigs (cops) because nobody else wanted to do that bullshit at first.

So when criminals were loaded up in a carriage, the wagons were called 'paddy wagons' due to cops mostly being Irishmen and back in Britain paddy was a slur for an Irishman.

I do apologize for my fellows for being pigs.

Maybe this is common knowledge? I'm not sure.