Yes, opinion-based questions should be avoided. Yes, if they're not closed, they should be answered fairly.
Previously, I had proposed the following guidelines:
- Posted answers must be comprehensive within the scope of the question as-asked:
- If the question is asking for an answer according to Sunni jurisprudence, it must cover all (significant) differences of
opinion within "Sunni jurisprudence".
- If the question is asking for both a Sunni and Shi'ite perspective, it must cover both Sunni and Shi'ite perspectives.
- If the question is just asking for what "Islam" says (remembering that for the purposes of this site, "Islam" covers each
and every group that self-identifies as
Muslim), it should
probably just be closed as "Unclear what you're asking" unless it's a
matter which has little to no actual difference of opinion across
every possible Islamic perspective.
- In cases where an answer covers a significant difference of opinion, posted answers must be free of obvious bias
- Under the principle of writing an answer for everyone who would ask that exact question, any posts which present any side of an
opinionated debate as "more correct" should not be
What you're bringing up here is a rampant problem on this site (whcih I've also brought up earlier), and has been so since the earliest days: Users insist on using the site to preach Islam, rather than out of any actual academic interest in the topic of Islam. Actively discouraging this sort of behaviour is at least as important as writing fair answers (if not moreso) otherwise those gems will just get drowned in opinion-noise anyway.
As a moderator I have been doing my best to keep things clean, but due to natural limitations in my own expertise I can hardly be expected to know what is or is not "opinion-based" in every single possible topic: I close what I can of whatever comes across my own radar based on my own knowledge, and after a while will often go through and delete closed (and apparently abandoned) questions which lack valuable (read: both fair and informative) answers, but the site has grown well beyond the point that any single person can be expected to handle all of it, whether or not he has a diamond by his name.
About the only way to solve this long-term is to build a critical mass of users who actually are interested in the academic study of Islam and willing to work together to curate a site which encourages the academic study of Islam (and actively discourages preaching and bias). Of course, this is very much an uphill battle as many of the users who actually would be interested in the academic study of Islam would only participate here if the site actually looks like a place where the academic study of Islam is actually encouraged.
Stack Exchange is built on community, and this is very much a community problem. At an individual level, the best I can recommend is to do whatever you can to discourage bad questions and answers and promote good ones instead (which is basically the same as on any Stack Exchange site: Vote early, vote often). Ask good and interesting questions, write good and interesting answers, encourage others to do the same, and basically hope your example sticks with others.
And be mind-numbingly patient, because this ain't gonna fix itself overnight. Every little bit helps, but we need a lot of "little bits" to have any hope of solving this.