Although the Kurtz family can't be proven to be Loyalist that doesn't mean that the heritage isn't Loyalist.
Starting with Rhoda Pettit. Her family is definitely Loyalist. Her father was a Captain in the combined Maryland Pennsylvania Militia. He is listed in the records of Loyalists.
Supposedly Mary Taylor said the family was Loyalist. I think she was referring to the Taylor family. There is evidence that could be correct but it will take alot more investigation to prove that one.
Anyone ever wondered where Harold John Gray Kurtz picked up the name Gray? I was thinking it could be a surname from a generation or two back but found something very interesting when I typed in the name Harrison (Rhoda Pettit's grandfather) into the Loyalist records search engine. There was a Loyalist by the name of Gray Harrison. This man has a fantastic history. He is the history of the USA. He came from Boston. He was in on the Boston Tea Party. He was his Majestys Council and Treasurer of the Province of Massachusetts Bay. He had business dealings with John Adam and John Hancock. This is very amazing family history and I would suggest someone start digging into it.