Disagree.
They have no moral obligations to him other than those they would have if he were not a public figure.
You’re missing the point entirely and that argument makes no sense.
They have a moral obligation to repay him for saving their lives. And Zimmerman is in danger precisely because he is a public figure. To ignore that makes no sense. It is the very thing that gives them the opportunity to return the favour in a small way. As far as we know it makes no difference to the other guy whether they hold a press conference or not. But is is clear that Zimmerman desperately needs a better (more truthful) public image. To him it can be the difference that decides if he is shunned or not, or it can literally be a matter of life and death. For them to shirk away from supporting him when he needs them is just plain despicable. So what that he’s a public figure (which is really a polite way of saying villified and persecuted)? That doesn’t mean they owe him any less.
Imagine if their other rescuer has someone wanting to beat him into a pulp. And further imagine that they deny taking him in if he’s on their doorstep. Would you then argue that they owe him no more than they would someone who isn’t being chased by someone who wants to do him harm? Because that is exactly the same principle.
You speak as if holding a press conference is some sort of gift or excessive reward. It is not. It is the very least thing they could do for a man who essentially is living with a price on his head due to bad PR.