I fully agree with you that it would be only fair for the ladies to be able to make 'PRIVATE' comments.
The problem right now is that the software will only allow PRIVATE tags to be toggled for for one group.
If they did allow for the ladies to have a form of private tags then each group would have to have a different tag name.
Maybe call the tags PRIVATE for the men, PRIVATE2 for the ladies or better yet call the tags for the ladies WHISPER tags.
That way the ladies could 'WHISPER' little bits of information back and forth about the guys.
I do know that it has been talked about, just not sure how far up on the owners wish list it is right now.