A reviewer is only able to add public comments - they cannot add admin comments and allow their identity to be masked. Provide the ability for any user to make a public comment, but to be able to indicate who it is from.
The issue is that we don't want to always expose names because that can lead to anyone able to guess at their email and find them in the directory, which in turn leads to more spam. We also do not have the bandwidth to answer all emails and phone calls. Thus, being able to retain their reviewer or contributor license and log a comment, but with the display their role or a generic title - similar to the same reason there is an Admin response.