Coupla reasons for that:

One of them involves available software.

Another involves my time, which I don't have anymore, and the appearance, at least, of even-handedness. If I only can check in a couple times a week, and it appears that I only notice one person, not the other, in an on-going custody battle over a topic (though it could be over the child or the dog) because of that timing, and we have already argued too many times about the same thing, I just let it go. Honestly, I have enough to do keeping teenagers from throwing things at each other and pulling toddlers off the windowsills. Doing the same in virtual space to/for grown-ups is simply too ridiculous.

Re: proximity of topics: Speaking with my professional hat on, lots of things live in the same stacks together. I think especially of the little Jackson collection in Biography: Andrew, Jesse, Michael and Stonewall, all lined up next to one another. Bigfoot is not in the Zoology range, and crop circles are not in Astronomy or Engineering. Bigfoot and crop circles are in the same place, along with the Bermuda Triangle and UFOs: a range in non-fiction called "Controversial Knowledge". (I could make a case for crop circles being placed in Art, but that's another discussion.) So far, no spontaneous combustion on the shelves.

I can maintain the little mental divisions necessary to balance the collection because I see how things work out in the public: when a topic is forbidden, people who don't know much about it will assume that something's being hidden from them, which feeds the belief in conspiracy. (We encounter this frequently in the Biology range of the Science section, when people of a particular religious persuasion notice there are no Intelligent Design books. Obviously, librarians are in cahoots with the scientists, who are out to get them. I can puncture their paranoia by directing them to the Religion section, where they can find what they're looking for.) Information, even information of dubious validity, is therefore best not censored, but managed in other ways. Location is one of those other ways.

The problem I see with this particular post is not the material itself, which is Off Topic, but the obscured authorship, which you addressed. Nick's solution, to register participants, is the only one I can think of that can be enforced by someone who doesn't spend part of every hour reading posts and checking up on authorship possibilities.

The underlying issue is the lack of meaningful discussion overall, that is, a reasonable give-and-take. Our discussion here amounts to something like this:
"A."
"Z."
"A."
"Z."
"A!"
"Z!"
"A, you moron!"
"Z, you fascist!"
Or add your own colorful appositional phrases. We all know what they are. I'm especially fond of "They did it too!" and "Stop touching me!" It takes me back to my 20s and early 30s, when my children were small and my joints didn't creak so much.

Sometimes it ends before that, or sometimes only people who agree post to the same thread. But we have precious little room for growth, because we don't allow self-criticism without the dogpile effect.

The response to TB's reevaluation of his opinion on torture, for instance, was painful to watch. He exhibited courage when he dared to question his own position. Not much of the response recognized this, except in a backhanded, what-took-you-so-long way. It's enough to discourage people from daring to learn and grow, or even from taking the relatively common step of changing one's mind.

We also seem to have lost the ability to agree to disagree graciously, something of which I'm as guilty as anyone, and more guilty than some.

If Robert wants to ditch OT, I won't cry. We talked about my resignation months and months ago. One of the things I've found most disturbing, personally, is a kind of aversion therapy I have experienced re: my enthusiasm for space travel and the science that supports it. On an emotional level, I've come to associate the reason I came here originally with grinding my teeth and high blood pressure. This can't be good for efforts to continue programming and displays that promote space science and engineering among the children in my little town. When one considers that I'll never be an expert in this field, and remain unqualified to comment on the contents of the Space board, this aversion problem negatively effects my ability to make the only real contribution I can make to space exploration: exciting children's imaginations with real-world stuff.

A parting observation on content: To place something on its own shelf doesn't contaminate other things placed on their own separate shelves, but to forbid its presence anywhere in the collection means one has lost the opportunity to refute it as well.

It does rather depend, though, on who you all want your users to be. Who is that?