Disagree; I think he's subtly knifing Superman in the back. He knows that, even grief stricken, Lois isn't going to hear an out-and-out attack on Superman, so instead he's playing on her fears. The unspoken implication here is that sometimes the love of your life is just going to be too *busy* with other concerns to save your family. No, *I* don't know how that could happen, but there must be a reason, right? Because if there's not a reason, it would almost be like he doesn't actually love you at all....
So yeah, somewhere between 'damning with faint praise' and 'sowing the seeds of discontent.'