Although I believe Cheney is sincere about his wanting the most for his daughter, there was also some calculated politics in his not saying much more on the issue of gay marriage and just thanking Edwards for his comments.

He couldn't risk ticking off his conservative base, and so it would have been a bad move on that front to have gone in to it any further. By not saying anything more, he avoided making the conservative elements of his own party any more uncomfortable with his views of his daughter and her sexuality.