Perhaps they know a snake oil salesman when they see one.
My dear mom once gave me a hot lecture about "yankees" when I dared to point out the Civil War unionists in her own family tree.
Besides embarrassing the poor old dear you drug up a painful past. Not many people like their dirty laundry hung out.
Here's a link to a Google book of a contemporary (1866) book on life in East Tenn. during the war:
Here's a better one: Jack Hinson's One Man War
And I'm sure you'll be happy to know that as my mom got older and I got wiser, I quit teasing her about her unionist relatives and focused more with her on the fact that she did have some true bonnie blue Confederate forbears who fought the good fight that she could be proud of.