The situation is actually a bit worse than that. As soon as Barry replies, Adam becomes the only person on the to line and everybody else is moved to cc despite all of Adam's hard work to distinguish recipient types up front. To vs CC is basically broken in threaded conversations. Moreover, unless you turn on some hidden options there is no visual indicator telling you who was on the to line vs the cc line in the Gmail inbox anyway. The distinction has become meaningless for the vast majority of cases.