Maybe he thinks you're trying to take over as Alpha dog and he is trying to protect his position???

Or maybe he just finds it plain annoying and wants you to stop, or it could sound to him like fingernails on the blackboard do to humans, or it could be dozens of other reasons, etc, etc, etc.........

If it bothers you that it bothers him, why not just don't do it????

Be a good boy poochie - no one is going to hurt you. By the way - does pooch have a name and a picture to post????