A big mistake, but I think it’s part of her proper Midwestern Methodist upbringing that crops up from time to time. There’s no way she actually thinks or expresses that kind of thing privately. And I think the candidates were asked to say something nice about each other. She shouldn’t have taken the bait.
This tendency is something I would have advised her to get past. In this age of all kinds of direct communication (before radio and then TV and internet) hardly any voters ever saw anything of a candidate other than reading a speech in a newspaper. Before around 1880 photographs were not even reproducible in print. Being a straight shooter is a better look than trying to be polite and sociable.
She talked about Trump upstaging her by looming behind her in a debate and said something about what was she supposed to do, turn around and confront him. Yes, that is what she should have done.