I have some sympathy for Sergei's position, because I found his questions to be interesting. I do suspect that if somebody else had asked exactly the same questions in a different way (phrasing and framing questions is so important on the internet!) then they would not have been closed. In my opinion, Sergei's remarks fall well-short of an ad-hominem attack, and in my opinion what he says has the merit of being correct. Conversely: Sergei, you shouldn't have named the moderator, because it wasn't relevant. It significantly weakened your argument. It doesn't matter who the moderator was. On the other hand, this is a special case- although surely it is the case that other good questions have been closed, I cannot think of any other examples which are similar to his own. So, in a sense, I think his argument in this thread is off-topic. Clicking "close" is quite easy, so maybe we should be more careful before we do it.
Alexander, I appreciate your support, but your words – “those who are still doing it hope for some support and understanding” -- can be understood in such a way that I demand some preferences for Russians. That is not correct, my message is another: the rules of the game must be clear, simple and equal for all participants. Of course there appear “soft questions”, but if you let a question pass (this means that you already agreed that this question is acceptable), then it is not nice to delete the accompanying specializing questions like “where is this written?”Similarly, there must be a space for appeals (and the explanation where people can do this). Fortunately , these problems are solved in MO (except for the right to appeal still is not prescribed in the rules). But in google groups that was not so.
Angelo, our beliefs are results of our experience. I tried to show here that what is quite natural inside the club can look absolutely unseemly outside of it. And vise versa (as you have correctly noticed). That is why if the rules of the game accept the idea that all representatives of the profession can participate, then the organizers should take into account not only their own opinion, but the opinion of the outsiders as well. In particular, the organizers should verify if their definition of “insult” coincides with the ones in the other parts of the world (because you see, our definitions of this notion -- yours and mine -- are different). Thereupon, if the organizers don’t like some natural mathematical questions, they should think over very thoroughly how they will explain to the others why these questions are forbidden. Because, as you could see in what I wrote before, if, for example, you want to forbid questions about axiomatization among mathematicians, it is not enough to write something like “this is off-topic”, or “…a sign of crankdom”, or “trying to figure out if f=g is precisely trying to figure out if f-g=0” -- your logical chain must be much more sophisticated. Very, very sophisticated. And convincing. Otherwise your policy will be perceived from the outside as a typical insult.
Daniel, mentioning names is also a display of the difference in cultures. In Russia when you criticize something you must give concrete examples, otherwise what you say will be “too abstract” (“голословный”) -- nobody will pay attention to you criticism, if you don’t refer to concrete facts and don’t give concrete names.