At least one moderator has been unilaterally closing questions (e.g. with the first vote, for "missing context"). In the past, it has always been agreed that moderators should only use unilateral closing powers in cases where there can be no question about the decision (e.g. blatant spam). For other matters (and esp. for contentious matters), the community should use the SE-designed process to close and reopen posts as the community sees fit. Such decisions should not be made by a single member of the community. Do we still agree about this?
For those who many not be aware of the history. In the early days of MSE we did have serious problems with moderators closing questions that they personally felt were off-topic, e.g. too applied, or too elementary, or too computational, or too foundational, etc (questions that would surely be considered on-topic nowadays).
Thanks to Martin for pointing out a recent thread by Brian M. Scott about essentially the same issue (I was not here when that was posted). There Brian refers to such unilateral closures as an "abuse of [moderator] powers", a sentiment that I strongly agree with. This may well be the reason that we lost Brian. It was the reason that I left the site last year. I am very sad to see that not only do these problem still remain, but they've gotten much worse. How unfortunate for MSE.