You won't be able to see who has left a comment in a Pod if you have the Enter Email to view Pod set to 'No' in the Security & Settings when sharing the Pod.
All users that comment will be displayed as Anonymous viewers.
If you want to see who is viewing your Pod and commenting you can change the Share Security & Settings. Select Enter email to view and change this to 'Yes'.
We have a detailed article that reviews How to share a Pod and how to change the settings here: