Although I have been working in various ways with the Internet since 1994, I still hesitate to post questions here because I have gotten some very know-it-all kind of rude replies. You asked for my opinion...
When mods are participating in a discussion, they should not also moderate that discussion.
If they think a discussion they are part of needs moderating they should ask an admin, or at least another moderator to take a look at the discussion and let the admin or "other-mod" make the decision about moderating the discussion.
[It's too easy to make your point prevail when you can delete the other position from the discussion.]