First of all, let's point out that it has only been downvoted by a single user (and was then deleted by the asker). As much as knowing why a question might have problems in order to understand how to improve it or engage the community about it is helpful, single votes are also not necessarily strong pointers to general community opinion.
That being said, we can still speculate why it might have been seen as problematic, keeping in mind however, that this is really just speculation. But when looking at the question
It might fall into a question category that has been discussed on meta before, namely "hey, I think I found a plot-hole!" types of questions along the lines of "Why doesn't Arnie need to reload his gun when shooting about 5 thousand thugs in a row?". These questions can be controversial (also depending on how they're asked).
I'm not saying it was necessarily posted with exactly this motivation and nothing precludes that question from actually having a reasonable and insightful explanation. But it might very well have looked like this kind of question to the single individual that downvoted it. Sometimes it comes down to the wording of your questions, too.
But this is all just speculation and the question is deleted already.