Hmm, not sure what would have happened to a thread questioning the removal. There isn't any system that pulls threads based on association or anything like that and I didn't remove anything.
Were you the poster? If not the person who created the thread could have removed their post, which would have removed it. Other than that I'm not sure what would have happened.
As a side note: I'm still waiting for the release of a final update to different message board software that I'm hoping to migrate too. Hopefully the new software will eliminate many of the problems I'm having with this system. Primarily the fact that I'm now having to manually sort through all of the requests to register for the message board and find the few real people. We're getting about 150 spam registrations a week. It also should add some new features for message board members, etc. If you'd like to look at what I'm hoping to move to you can find information about it at phpBB