First, I'm not aware of any topics that have "disappeared (i.e., were deleted) from that forum within the past few days, other than as detailed below, and I check that forum frequently each day.
Second, the TUG BBS administrators and moderators consist entirely of unpaid volunteers whose charge is to fairly administer the posting rules as detailed in the "Site Rules" (link on the blue bar above). Thus, there is no "relationship with RCI" that volunteers seek to protect.
If such a topic was inadvertently deleted, I invite you (or whoever posted it) to post the message again.
However, if a topic was deleted, there are several possible reasons. I note for example, that one recent message on that forum was deleted with the explanation (still on the forum) that the message was a duplicate post, which violates the BBS rules.
There is another post, worded in a hostile manner, that is a duplicate of perhaps 15 or so messages which Madge has very patiently answered on that forum over the past six to eight months or so. That posting, in the judgment of a moderator, was closed, not deleted, although from the explanation, I can't be sure if the reasons I have suggested here are the true reasons for the closure.
That brings up another point. RCI has no obligation to respond to questions here at TUG. If we want that Q&A dialogue to continue, we have a responsibility to be courteous to Madge and ask questions in a courteous manner. The risk of being rude, arrogant or accusatory, rather than simply posing questions, is that RCI (or Madge) will take the same road that II did and quietly give up trying to respond to our questions. No one should forever willingly take the kind of abuse that is often offered on that forum. Thus, the moderators have a responsibility to help control the dialogue.