One can be concerned about a their child's morality without being openly judgemental. I am sure that "whatever makes you happy" was not the only words father Cheney said to daughter Mary. However, the difference between Cheney and Keyes, is that both father and daughter had the class not to make this a public debate, feeding the "beat them over the head with a bible" group of faux-Christians.
Children are only ours to form and nurture while they are children. Once they are adults and responsible for their own actions, we can approve or disapprove, but we must treat them like adults. Publicly stating that you don't approve of your daughter's lifestyle is a disrespectful way to treat another adult. Publicly stating that you don't approve of someone else's child is a slippery slope most Christians in public life shouldn't stand on.
You're quite rejecting Christianity...for the religion of humanism. Homosexuality is sin...its worth noting, especially when its being displayed quite publicly in a tell all book by the Vice President's daughter. What is disrespectful...pointing out immoral behavior or immoral behavior. We don't need you treating Christians like dummies..
I think it is an impossible line to draw when you say, "One can be concerned about a their child's morality without being openly judgemental." If your concern is kept to yourself what value is it? Parents should instruct and guide their children, sometimes even when they are adults. In the Bible, you learn over and over that those whom God loves, He disciplines and corrects. We love our children best by speaking the truth and guiding them to the right path. Permissiveness, weakness, and lack of moral courage are not love.