I'm just reading the sign that a New Yorker put up.
... you probably think red sauce is gravy too.
(yeah, I said it!)
Does it have meat ?!? ... then it's GRAVY !!!
What about MEAT sauce??????? Gravy comes FROM meat, not includes meat. Just sayin'
Simply
(did I spell that right?) put, you are right - sort of - ...I look at it this way - one can have butter sauce, wine sauce, apple sauce, whatever sauce, but since gravy comes from meat, it is GRAVY not SAUCE ...
Our Sunday GRAVY was FILLED with meat ... just sayin' ...