Grand visions of secret police say more about you than they do about scubaboard moderators.
And I say this as someone who has been through this exact argument numerous times starting from BBSes in the mid-80s to Usenet in the early-90s and now on to internet web forums. And before I burned out on these kinds of arguments I typically was on the side of those who were 'fighting the power' so I know exactly where you're coming from. And I know from prior experience that these arguments either end by the users deciding they'll put up with the sysops/moderators or the users going off and starting up their own BBS/forum. In fact I can think of two scuba forums off the top of my head that have been spun off of scubaboard for arguments similar to this (not exactly the same, but history rhymes rather than repeats).
None of your civil rights are being violated by moderators 'disappearing' threads with no public explanation of why. If you don't like it, set up your own forum and come up with your own rules. That'll actually satisfy your need to be in control which no amount of public argumentation on scubaboard ever will.