If you believe that, then I would suggest you go read the book of Philemon--an entire letter from Paul urging a runaway slave to return to his master. Never is there a word uttered that the institution of slavery is morally wrong. People thus took that to mean that God condoned slavery, and it's not difficult to see why.
Such as the growing mountain of biological evidence that homosexuality is not a choice, and in fact is something that people are born with? This was something that was not considered at the time the Bible was written.
And thus highlights the problems of basing all of one's decisions--moral and otherwise--on interpretations of the Bible. People are falliable, and their interpretations and understandings of certain parts of the Bible inevitably turn out to be wrong or misguided. You highlight two good ones above, although there are many more. (People used to be put to death, for instance, for claiming that--God forbid!--the Earth was round and not the center of the universe. Others believe that the Earth is only around 6,000 years old. You get my point.) How can you be certain that the church's commonly-held opinions on homosexuality are correct? Why would you risk ostracizing your daughter over a church's interpretation of the Bible?
back to Alan Keyes--it's impossible for me to view this as anything other than a political move by him. As another poster pointed out above, if he is *so* concerned over her immortal soul, why did he wait until she went public with this information before cutting her off?