[nine_k]

A "not relevant" question is usually not a "bad" question, but just a question that can't have a good, definitive answer. SO are trying to be a site hosting such answers, not discussions.

So opinion-based questions are explicitly unwelcome on SO. They can collect lots of worthy information in comments, so such questions are usually closed but not deleted.

SO even tried to channel the discussions by developing discourse.org so that interested parties can get a them a discussion forum and continue there :)

[jsmeaton]

It was Jeff Atwood (and friends), not SE, that developed discourse. One of the reasons he headed in that direction was because of the discussions that weren't appropriate for SE sites - but it wasn't SE trying to fill the discussion need.

[nine_k]

Yes: it was owners' efforty, not a community effort.