I have just submitted my resignation as a moderator on this website to Jeff Atwood. I would like to use this thread to explain my reasons.
When I make a significant time commitment to a given organization, I expect certain standards from that organization. I do not, of course, claim these to be universal or objective, but simply that they are my preferences. Among these is the free expression of dissent: namely, I highly value the opportunity to criticize management, with such criticism considered sincerely, and not suppressed. When I campaigned for the moderator position, I promised a change from what I viewed as some of the drawbacks of the pro term moderator's handling of meta: most importantly, I promised to keep it more open, and in particular refrain from needlessly closing or (even worse) locking threads.
It has become clear to me that these values will not be practiced on this website. Mr. Atwood, a moderator across the StackExchange websites, has recently removed two mildly critical comments of Pete L. Clark under the claim that they were not "constructive"; he has, moreover, announced that he will continue to practice such deletions, potentially without notification either to the mathematics moderators or to the commenter, at his discretion. Having observed Mr. Atwood's standards for "constructiveness" (as opposed to offensiveness) both on this website and on meta.SO, I am deeply worried about the possibilities of this.
It is unfortunate that the present situation is not an isolated incident. Mr. Atwood has in the past, for instance, locked threads he found insufficiently deferential. He has suspended users over mild comments, and has in comment threads rather harshly suggested that valued contributors leave if they did not agree with his philosophy. He has, apparently, deleted a critical comment on the linked thread. I have, in the past, requested Mr. Atwood not to engage in such actions, which I, as stated above, view as highly undesirable in any organization. When I took the moderator position, it was with optimism that Mr. Atwood's past actions were impulsive reactions to the admittedly chaotic climate on meta.math.SE in those days, and not a trend to continue.
Unfortunately, after recent events, I am now convinced that Mr. Atwood in fact places little value on free expression on his websites. I strongly disagreed with Mr. Atwood's unilateral deletion of two of Dr. Clark's comments, and started a thread in the hope that airing the issue openly, and stating clearly my reasons for disapproval in a public forum, would convince Mr. Atwood that he had made a mistake and thus induce him to follow a more strongly non-interventionist policy in the future.
I initially had no thoughts of quitting when I started the aforementioned thread. However, Mr. Atwood's adamantine reaction, an unqualified defense of the deletions and an affirmation of his willingness to continue such policies, left me in the position of proposing a compromise, as I promised to do in the comments. The only compromise that I could see that would satisfy Mr. Atwood's demands seemed to be the following: Mr. Atwood would leave all other site moderation to the usual moderators, and exercise his jurisdiction (of removing "unconstructive" comments) only on SE initiatives sponsored by him. But it soon became apparent to me that I could not accept a compromise where Mr. Atwood (or any other SE moderator) can stifle free discussion just because it does not please him, even on a subset of threads. There does not seem to be a resolution.
I do think that the present website has significant potential, and I have been impressed by the quality of the answers here, many supplied by professional mathematicians. However, as I stated above, there are certain standards I would expect from an organization to which I am volunteering my time, which I can after all use in different ways. To give an extra-mathematical analogy, I am happy to admit that the Salvation Army's work probably provides significant assistance to homeless people, but their homophobic record would make me never consider working for them. (This is an analogy and not a comparison.)
In view of this, it seems best to me to retire as a moderator. I will probably shy away from the entire website for a few months at least; while I may return to the main website later as a regular user (I think I am done for good with participating on meta), recent events have left me disinclined to do so in the near future.
I apologize to the community for any inconvenience caused by my departure; it is a disappointment for me, too, to leave after only a semester on the job. Nonetheless, it is questionable whether I should have been a moderator in the first place (I did not, after all, win the election); and if an election is not held any time soon, Qiaochu and Willie are both extremely capable moderators who could certainly manage without a third volunteer. My apologies in addition for having started the thread on Mr. Atwood's actions. In retrospect, it seems to have generated more heat than light, and my assessment was probably incorrect; handling it by email might have been a better approach.
Finally, I would like to thank the many members of this website who have kindly answered my questions, helped me improve my own answers, and otherwise offered support. Since I have said some harsh things above, I would also like to clarify that I hold no personal vendetta against Mr. Atwood: on the contrary, even if I have disagreements with him, I rather admire many of his ideas, such as the systematic use of copyleft, and I hope that the present website will continue to succeed.