The question to me does not read as a non-constructive question. It would have not been my vote. I would have however voted to close it as "Not a real question".
It's vague, skimpy on the details, no clear prior research besides some vague statement, no real attempt at a solution.
[...] and there's a nice variety of answers there.
That doesn't really matter for closure. Closure mostly relates to the question asked. A poor question with a brilliant answer can still be closed because it's a poor question. The answer does not influence that a whole lot.
Overall, the question and answers seem to have been well-received; there are a fair number of upvotes and "stars," and not many downvotes.
Keep in mind that in internet-years this question is quite old. And the site was quite different then. Some questions that were quite appropriate then would no longer be appropriate now. And even now, popularity of a question does not necessarily imply appropriateness for the site.
So in summary, I do understand the closure of this question. My reason would have been a different one though. But that by now is a moot point.