We deal with a very large number of flags on Stack Overflow every day, sometimes the number climbs over one thousand. I'm the one who closed the question, and I'll explain my reasoning and then elaborate a bit more.

It wasn't just me that closed the question

While I am the only (and super) vote involved, I was reacting to multiple flags from high reputation users of Stack Overflow, who had (likely) ran out of close votes themselves. I agreed that the question was quite difficult to understand, I also agreed that the community tends to react negatively to questions that basically boil down to "please run my code and tell me how to fix it".

Closing is not a permanent state

If we want to close a question with prejudice, we also lock the question to prevent even high reputation users from modifying, un-deleting or re-opening something that simply does not belong on the site. Users are still free to disagree with us, however a discussion must happen (here) before the decision is reversed.

Simply closing the question stops the flags and rude comments and gives the original author time to improve their question with feedback from the community. If a question is sufficiently improved, it can and should be re-opened by the community, or reviewed and opened by a moderator.

The text provided under the closure notice is not at all difficult to comprehend:

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form.

If the user is not able to understand this, there's a very good chance that the user is also unable to sufficiently improve their question. This doesn't mean the question is going to go off to the meadow and die, but it will need some help from experienced users in order to be edited into shape. Still, during this time, the question needs to remain closed, or we're sending a clear message that we'll accept content that contradicts our quality guidelines.

Many poorly asked questions are never improved by the author

There are some users that quickly catch on to how Stack Overflow works and improve the quality of their writing as well as their interaction with the community. Unfortunately, most of the time (as of late), this simply is not the case.

I have, on may occasions left comments strongly suggesting improvements, only to visit flags the following week to realize that the advice was ignored or perhaps never even read. None of us have the bandwidth to star ever single thing we mark as needing improvement. To prevent disruption to the community and keep our quality bar as high as possible, our only choice is to close or improve poor quality questions on sight. If a question is really bad, beyond the point of being salvaged, we may elect to just delete it so it doesn't block a better attempt at a similar question.

I did consider improving the question

I clicked the edit button, started to edit and gave up. I could not accurately tell what the OP really wanted, beyond someone to run their code, point out the bugs and indicate how those bugs could be fixed.

With 200+ other flags in the queue, my best option was to cast my close vote and move on to other more urgent flags.

Given the current popularity of Stack Overflow, we have to realize that not everyone can be helped into our community. The trick is identifying those who can, then helping them. If the author of the question had made even an attempt at improving it to the point that the actual question could be discerned, I would have happily spent more time helping them make additional edits and re-opened the question.

Even after help from someone else in the community, the question as it stands now is still not suitable to be re-opened.