Most cultural myths of bygone eras, especially ones about the past, are bullshit, but I'm pretty sure the cultural myth about the South was more "if you try to date my daughter I'm going to get my shotgun" not "please try to feel her up at the mall, kindly respected gentleman."
That isn't in contradiction to notions of women marrying younger, etc. You called her father and asked for permission. You didn't sneak in through the bathroom window.
These are all myths, of course, I'm not asserting any of it as true, I'm just saying that those myths involve honor and respectability (whatever that means), not creepy old men. Wear your tuxedo to the debutante ball. Don't creep her at the arcade.
