We don’t exactly have blue bloods in the United States, but I’ve certainly observed the same phenomenon here. I was brought up working class and taught not to swear, because it would mark me as low class. Later, as an officer in the Air Force, I was told swearing was something for enlisted people, that officers should avoid it. It was a class thing.
But later in life, I worked at a New York firm staffed with several members of very old, very wealthy New York families. The kind who live on the Upper East Side and whose families have lived there for generations.
To a man and woman, they swore like troopers.