It seems as though one is not able to comment on a shared item unless the owner has commented first. Is this intended/desirable? I can understand how this might not be desirable for some people, but a friend just shared a comic that I'd like to comment about and the option doesn't show up.
I agree that it's fine to not be able to comment on a story that hasn't been shared, but you also can't comment when someone has shared an item without a comment. That doesn't seem desirable; isn't the point of sharing a story with your friends to start a conversation?