I'd like to make the case that mathematics education certainly has a role on MO (it's of interest to research mathematicians!) but that asking good questions about mathematics education is genuinely difficult. This doesn't mean we should expect a lower standard for these questions, but rather that more work be put into asking them!

(For the record, I had nothing to do with closing or reopening the question that prompted this thread -- my involvement so far has been trying to explain why "subjective and argumentative" are bad qualities for a MO question. In the present, revised, form, I think it's an excellent question.)

Quoting from the FAQ

As a side-effect of being very good for to-the-point questions and answers,
the Stack Exchange software is bad for disscusions and designed to minimize
them. There's a place for discussion about mathematics, but it isn't MathOverflow. 

Hopefully by now we all agree with this --- MO questions shouldn't explicitly encourage discussion or argument. Rather, they should aim to provoke definitive answers, that can be identifiably "correct". Now, this is obviously difficult with many mathematics education questions. I think the best way to do this is to phrase questions as neutrally as possible, and to ask for answers that are not just opinion or anecdote, but can be backed up by evidence. Ideally, evidence provided by actual studies of mathematics education. (I think I heard this first from Ben Webster or Scott Carnahan: hopefully they can argue this more convincingly for us!)

Now, I appreciate that this ideal is a high one. I certainly agree that in many cases anecdotes from experienced teachers are very valuable, and we should respect and encourage these when appropriate. But I think we should actively discourage people like me, with limited teaching experience, from jumping in with answers that are merely opinions. A good mathematics education question will be asked in such a way that makes this clear!

Finally, given the extra difficulty in asking mathematics education questions that will produce impartial, evidence-based answers, I think it is particularly important that these questions are not themselves too opinionated! This can only hurt the chances of the resulting answers. I think in the case of this particular question, the initial phrasing was quite opinionated, and this may have provoked the initial closure (which, I reiterate, I had nothing to do with!).

@Michael,

as has been said many times on meta (I understand you're not a regular, but still): the existence of a unclosed question that is strictly worse than some particular closed question is not regarded as evidence that the closed question was closed in error.

If you're speeding, and you get pulled over, do you think you get off scot-free if you tell the cop that the guy in front of you was driving much faster?

Michael, it sounds like instead you're saying "but everyone speeds".

@Michael Hardy:

When MO first started up, most of the rules and policies were not as strict as they are today, and a lot more bad questions fell through the cracks. Since then, the closure policy has evolved to take care of new problems as they arise (in the early days, Scott and Anton were singularly responsible for the vast majority of closures, for example). The newer policies here are often proposed by the moderators and put into effect after some debate. If you want to debate the merit of Scott's new closure policy on pedagogical questions, you should engage it on its own merits. We acknowledge that this is a change (justified by a reinterpretation of the goals and rules of MO), so arguing that the policy wasn't followed before is silly.

Hey! I didn't express a "closure policy on pedagogical", nor did I have anything to do with the closing or reopening of this question. As I said above, the question that prompted this thread is an excellent one!

I was trying to explain why it is difficult to ask good questions about mathematics education.

I'll just note: MO is community moderated. Most of the moderation is done by whichever of a certain reasonably large group of users happen to be on the site at the time. Thus, it's obvious that moderation policy will be inconsistent. A large number of questions that maybe in theory should be closed slip off the front page before the people who can vote to close bother to read them. Our attempt to deal with this unavoidable inconsistency is to have this site to discuss how things should go.

I think (but maybe I'm wrong) that it's safe to say a question like the second one would be considered off-topic today. I am a little more ambivalent about the first question. In any case, it's hardly fair to say that a few slightly less objective mathematics education questions undermines the premise that questions on MO are generally intended to have precise and identifiably correct answers. Michael, are you actually suggesting that a significant proportion of open questions (from, say, the last few months) are like these isolated examples?