Motive? Doing something good is always doing something good on some level.
However, if Mitt had read about some poor black Baptist girl who was missing and the police weren't doing anything, and he threw the resources of Bain and his own personal resources into finding her? That's one thing.
If a daughter of one of his wealthy partners is missing, and the rest of the wealthy partners in the firm assist in finding her, using their employees to assist with the search? That's still nice, but it's a completely different story.
Not quite like the Crimson Tide Football Boosters club helping the family of some spelling bee champion in Wisconsin rebuild a storm-damaged house, versus the Crimson Tide Football Boosters club helping the family of the top high school football recruit in Memphis rebuild a storm-damaged house. But along the same lines. One impresses me more than the other. But both are nice.
You can play hypotheticals, but this is something that happened. And it was good. And other people may do good things too, and maybe they do them for people they dont know, but it doesnt diminish what happened.
If you are so afraid of Romney that you have to spin this as being bad because he had the motive of finding someone who was similar to him, then there is no point in further discussion.