Why might we want to provide terror suspects with meaningful trials in this country? Not so much because we think non-states, particularly terrorist groups, will reciprocate. Instead, it gives us the moral authority to demand a fair trial in pursuit of justice for others around the world.
National moral authority is not about being able to feel good about ourselves -- it's about being able to stand up for important principles around the world without looking like hypocritical jackasses.
One note -- I have no idea whether the accused Christians are guilty or not guilty or even innocent. I have no idea whether they received fair trials. But you simply cannot complain that these guys over here didn't get a fair trial when you endorse your own government's plan to hold people indefinitely without trial and then execute people based on secret evidence.