they're using it wrong. They're going upwards with it when bloodline is a line of descent. So your parents are not in your bloodline, but of course that's not what we were talking about since they directly said "Bloodline is the blood in you, mother and father, and their mothers and fathers, all the way back. Unc ain’t in your blood." Since they're including grandparents to infinity, your uncles and aunts are in that bloodline. You can read my comment for more..