I stand with Mark Cassidy's comments in Slack on this. If it has anything to do with Sitecore at all, it should be allowed to be asked here. This could lend itself to some interpretation though. For example, if someone were to ask "How do I populate a List object?". This person is using Sitecore and probably working with items, but his direct question is about how to use .NET List(). That is an example of a question that probably shouldn't be on here.
But maybe he MEANT to say, "How to I populate a List() with Sitecore items from a query?" Well, now we're talking about an answer where maybe using a IEnumerable converted from an ItemCollection would be the answer, and is very Sitecore relevant.
To be honest, so far, the only question I felt questionable thus far on the posts that have been proposed as Closed Voting, was the one talking about SOLR Indexes. SOLR itself is probably not something we want to dive into. But what if it's talking about the Sitecore Content Search API and using SOLR? Then that probably should be on here.
At the end of the day, though, I don't want this to be a community where members feel bad about asking "too-broad" of questions. Sitecore is a huge Yak that can be shaved in a multitude of ways depending on what you are doing. There are best practices, then there are BEST practices, then there are Worst practices.
I say let the debate occur here, even if it is too broad or opinion based.