He’s not just varying “if you’ve got nothing to hide”. He’s giving an active reason for sharing that you’re an exit relay, not just saying that you have no reas

He’s not just varying “if you’ve got nothing to hide”. He’s giving an active reason for sharing that you’re an exit relay, not just saying that you have no reason not to share, so you might as well. The reason for publicizing that you’re running a relay is that it reduces the probability of being falsely accused of doing illegal things that someone else was using your exit relay for, and it makes it easier for you to recover any confiscated computers. If you publicize your running of a relay in advance, then the prosecutor might see that fact and not bother prosecuting you, knowing that you were not the origin of the illegal traffic.