This is about Sunday Sauce. (Disclaimer: I'm not Italian, nor were any Italians harmed in the making of this post.)
Bon Appetit is saying that if you make Sunday Sauce without meat, it is called sauce. If it has meat, it's called gravy. What say you? I thought it was more of an Italian origin issue, as in what part of Italy your ancestors were from.
Sunday Sauce Common Mistakes - Bon App