I have observed several times, whenever I ask something that relates or compares two things, moderator puts it on hold saying that it will invite chatty discussion.
But why are there such policies? Sometimes, questions are so genuine and unique that very rare or no attention is previously concentrated. But just because they compare two things they are put on hold.
A very recent incident is this: https://stackoverflow.com/questions/21882080/java-support-for-multi-core-processing-vs-openmp-posix. This question is very genuine and almost rarely concentrated before. But just because it compares Java and OpenMP, it is put on hold. And I observed this mostly happens when Java is compared with some other technology. I suspect sometimes Stack Exchange is biased towards Java and it really doesn't allow to find pitfalls in it.
Doing this I think Stack Exchange discourages people from asking questions. Instead why don't you dedicate one site to such questions?
Being a leading technology forum, I never expected this from Stack Exchange. And I must admit that Stack Exchange is limiting its scope of exploring various technologies and their interdependency, superiority comparisons etc.
If Stack Exchange isn't built for such questions, then where should we post such questions? Because I don't find any other discussion forum as robust and complete as Stack Exchange.