Why do women withhold kids from their father after the divorce?

Women get angry when they get divorced. Even when the throw them out, they still get angry. They know that most fathers really love their kids and some women will use their children as a wedge. They think that by withholding the children from visiting their father, it will hurt the father. Oh, yes it will hurt the father, but it will hurt the children even more. I think they do it just to get back at their husband without thinking of how that affects the children.