Only individuals with both TDNext and Knowledge Base access can see the History and Feedback tabs. That includes the ability to leave Feedback/Comments on articles. Other than basic access to those applications, there aren't further controls or permissions that facilitate the ability to leave Comments on articles. Security Roles *do* have a permission around marking Feedback as addressed, but not one for whether someone can leave a comment.
Perhaps you could create an enhancement to ask for this ability to control, but it isn't current option to restrict.