> and while I find them very useful to read, I understand why SE do not like them.
This is exactly what I don't understand. If a question is borderline, but obviously useful, why not err on the side of allowing it to stand?
>Sometimes, I also see threads closed as homework questions, but those tend to have several duplicates which do have the answer in them, so it has so far not bothered me.
This doesn't happen anymore. The "Homework" tag was removed and is no longer a valid reason to close a question. That doesn't mean these questions don't get closed using other rationals of course.
I can expand why I think SE do not like "what is best ..." questions.
1: There is no definitive answer to it. At best there is best practice, and at worst there is flame wars. If Moderators tried to distinguish what topic could become flame wars, you tend to end up with very biased moderation.
2: Recommendations are much more time-sensitive than purely technical questions. The best framework in 2005 might be abandon in 2015, which can mislead readers. As a reader, I know this and always check the post date, but from a UI perspective, this key component is not obvious in SO.
3: Flame wars are destructive, and SE has historically tried to avoid them. Questions like "should I pick GPL or BSD?", "Emacs or VI?", and "Python or ruby?" tend to be cut down before they cause problem in the SE community. I wish sometimes that HN would follow suit and do the same.
I think it depends. "What is the best image processing library?" should be closed. However, if that person goes on to detail what exactly they are trying to do and what constraints they are working with, it may not be so open-ended anymore. And this is only an example of one type of question which is routinely closed. There are others.
This is exactly what I don't understand. If a question is borderline, but obviously useful, why not err on the side of allowing it to stand?
>Sometimes, I also see threads closed as homework questions, but those tend to have several duplicates which do have the answer in them, so it has so far not bothered me.
This doesn't happen anymore. The "Homework" tag was removed and is no longer a valid reason to close a question. That doesn't mean these questions don't get closed using other rationals of course.