I believe that forum mods should be permitted to involve themselves in any discussion and be free to post their views and opinions.
I would feel unfairly treated if moderators would be considered as only 'monitors' of the forum without any option of involvement in expressing their personal opinion.
Provided of course that it's done within forum rules.
Then, in my view that's where moderator impartially must be applied, in upholding and maintaining forum rules and guidelines regardless of personal opinion, friendships or associations etc.
Personally I see no problems in adhering to that principle.