As Rarity mentioned, many questions are not real questions or are not constructive (because every answer is equally valid and they are just asking for suggestions). If an "asking for suggestion" kind of question is not welcomed here, I am confused why there are so many question still standing. To me, they are all asking for suggestions.
How can we define question which need expertise and question which only need opinions?
It seems to me that there are plenty of "What should I do..."/"How should I do..." and those questions which are asking for suggestions for a behavioral question such as this.
If only expertise is needed, do we need the answer to state that "I am expert on this because I interviewed xx people" or "I am expert on this because I fire a lot of people in my life"? If they don't say this, how can we distinguish a simple opinion from a answer of an expert?