Divorce is a major factor in civility and manners.
Once one parent of a child in a divorce situation seeks to curry favor with the child disregarding the potential for the child to manipulate parents, the situation becomes ripe for disrespect and loss of parental control. You can spend an hour explaining what they can't understand or you can be the boss. People assume that if you swat your little one on the bottom you're begetting violence. People care more about their stuff than their kids. I have studied the issue at length and I have observed in daily life that this is so.