Gentlemen,
I cannot speak for the other Union field armies, but the Union Army of the Tennessee maintains an very open forum in the Old Abe Tavern and Parade Ground. There we indulge ourselves in all manner of role-playing and cammaraderie with anyone who wishes to enter, in a very direct and friendly manner. Anyone in the club can go there and read all they want, and posting is easily accomplished with the usual login drill of Username and Password. This includes our own officers.
The only forum areas that are shut to non-AotT officers are the Conference Hall and our Staff HQ. The Conference Hall is the secure place in which we accomplish our monthly Muster Call, a process wherein we not only signify our continued presence in the club, but where we relate in some detail the current battles in which we are participating. These "Muster Reports" contain observations and subjective material on our CSA opponents, material that is considered "military intelligence," and therefore classified. The AotT Staff HQ is another restricted area for obvious reasons. But, of course, none of this should cause such personal consternation among our Southern friends, nor engender such active ridicule.

We would expect similar guarded areas in the forums of our opponents.