It seems there are lots of questions in this Stack Exchange that are not fact based questions. If the higher reputation members have the ability to do such flagging, the evidence of it being exercised is not readily visible on the site.
An example of such a question might be "How can we trust xyz?". Something better left to a philosophy exchange than here. Many questions that start with Why... also fall into this category. I just looked at the top 10 most active posts and 6 of them start with "Why...".
The bias in certain questions might be hard for some to see, and there seems no mechanism (at least to newer members) to tag something as biased/opinion based/etc by some members so that other members might be alerted to such bias/opinion/etc.
To summarize my question: How can this exchange stay away from such questions and responses to stay a valuable forum for answering political science, etc, questions?