Two thoughts...
1). Alan Keyes hasn't thrown away his daughter, but has stopped funding her education and housing. His daughter has stated her understanding of his position and it appears that his only "condemnation" came in an unwillingness to fund his daughter's lifestyle.
2). How does one save souls if people aren't made aware that their sin requires salvation?
From your post: "Alan Keyes hasn't thrown away his daughter, but has stopped funding her education and housing."
Did you even read the article? It says he cut off all communication. It would be one thing if he stopped funding her education. But to cut off communication with a child because of she is gay is not Christian.