On top of that it's been closed since 2011 and nobody saw it fit to be re-opened. Not to mention having 100+ answers. How that's constructive is a wild guess.
But at least it's made some smile or catch them offguard.
On a related note, there's a blog post on the SO blog concerning closed questions, pretty interesting stuff.
I like questions like this being closed, particularly if they draw out a ton of useful information like this one. Maybe my pain could be eased a little if they had some better boilerplate explanations. To me "Not constructive" in this case is just misleading, wrong and rude.
"It is only relevant to a small geographic area". No, the question is just as relevant in Louisiana, Lithuania and Liberia.
"It is only relevant to a specific moment in time". No, the question is just as relevant now as it was 50 years ago and will be in 50 years.
"It is an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet". No, it an extraordinarily broad mathematical question that clearly has appeal to a very large, worldwide audience.
In western society there are almost always checks on the use of power. A policeman was too violent when making an arrest? He can be reprimanded or fired. Politician accepted a bribe? He could be locked up. Businessmen colluded to keep prices high? They could be fined heavily.
The 'justice' of our system is so pervasive that we take it for granted, which means it can be very frustrating to experience the unjust use of power without possibility of redress. This case is a minor example, but it must feel like a slap in the face to the person who posted this question on Stack Exchange.