They probably didn’t want to vote for either.
I’d vote for McCain over Huckabee, but since I really didn’t want either, I voted for Romney.
I'd definitely vote for Huckabee over McCain. But to your point, no, you wouldn't vote for McCain over Huckabee apparantly. You had your chance and chose not to. By voting for "no longer in the race", you left an opportunity for Huckabee. In reality, you didn't make any choice at all. You could have just as well stayed home. Same difference.