Today there was this question: Who is the most legitimate heir of the Iron Throne?
Which was put on hold as primarily opinion based, but it is not opinion based; it is a question that can be answered with quotes from the books (like @TLP said in the comments).
It is not a question like
Who do you think is the most legitimate heir?
In the books, all of those heirs' claims are explained.
I voted to reopen this question, but it was not reopened.
I cannot understand why this was put on hold.
Sometimes people get a bit overzealous with the vote-to-close thing. And sometimes they may actually believe that there is no canon answer to a question. In neither case, are the folks who voted to close necessarily correct.
If you see a question that has been closed as "primarily opinion based" and you have an answer which is based on canon information, then you should talk to a mod and/or bring the question up in chat. It's easy enough to get a question reopened, if you have sufficient justification for doing so.
Looking at it again now, I'm not sure I would cast the same close vote. It still doesn't strike me as being a particularly good question the way it's currently written, and - as mentioned in the comments here - may very well be a duplicate.
I think most of the issues come from that last spoiler tag:
What would happen if any or every of them would eventually die? Who could claim the throne? The one with the biggest army?
That's wandering very close to, if not directly into, the realm of wild speculation. The entire thing also reads (to me, at least) like a "I've read the books, I'm not sure who I think should have the throne, what do you guys think?" discussion-y question.
That's perhaps not the intent of the question, in which case it could benefit greatly from editing. I'd suggest removing the "Any other" part (that last spoiler tag) so it just focuses on those three who have explicitly been mentioned in the books, and making it clearer that it's an in-universe, "with respect to Westerosi laws" examination of the validity of their respective claims (assuming that it's not a duplicate).
I voted to re-open, but at the same time I'd suggest that the question be edited to narrow the scope by changing the first sentence to read:
After finishing the fifth book (A Dance With Dragons), and based on the information confirmed in the books to date, I'm not sure who has more rights to the Iron Throne.
The reason for this, and I'd suspect a reason why some may have voted to close, is the uncertainty and popular fan theories over Jon Snow's parentage.
If what is speculated by many turns out to be the case then it upsets the heirship somewhat, but since the author has neither confirmed nor denied that speculation it does mix some element of "opinion-based" into one possible set of answers.
Tightening the scope by excluding that possibility from any answers would also have the effect of removing the "opinion-based" element.
