I think that was a good response. By requesting the release of the hostages as part of the deal, that would give Iran a HUGE leveraging tool. By leaving them out entirely, it removes both sides ability to leverage the situation to their advantage. Imagine what Iran could of asked for in exchange, and watch the Media pounce on it as a capitulation if they gave in.
Seems like a big departure from what he said about the Bergdahl exchange:
I make absolutely no apologies for making sure that we get back a young man to his parents and that the American people understand that this is somebodys child and that we dont condition whether or not we make every effort to try to get them back.