I wasn't even aware of this situation when it happened, and I'm not sure how I personally would have voted/dealt with close votes, but consider this:
Our close reasons often overlap, and the "primarily opinion-based" consensus could probably have been phrased in terms of our engineering close reason:
This question appears to be about engineering, which is the application of scientific knowledge to construct a solution to solve a specific problem. As such, it is off topic for this site, which deals with the science, whether theoretical or experimental, of how the natural world works. For more information, see this meta post.
Problems where the solution depends on too many variables, or where the variables are not particularly constrained or even fully defined, are considered off-topic by association with engineering. The reason is, the correctness of any answer given depends sensitively on all sorts of extra information, much of it not necessarily related to any particular physics concept. For example, the scaling for how a beam deflects under a load may be a valid physics question, but a question that relies on the exact dimensions and material properties of some particular beam is not.
When the problem goes beyond universally-accepted underlying physical concepts, the only way to generate any solution at all is to make a number of assumptions. Thus engineering questions are generally also off-topic as opinion-based, simply by virtue of the fact that they ask a bunch of physicists/physics enthusiasts for their opinions to fill in the blanks.
As mentioned elsewhere, there were plenty of downvotes and surrounding controversy. I suspect the wording of the question was such as to amplify whatever response it was going to get anyway, and as I've explained above, the response was likely to be "this doesn't belong here" for one reason or another. This isn't to say that a little whimsy or an attempt to connect to current events/the Zeitgeist isn't allowed (I'm certainly guilty of titling questions so as to make them more attention grabbing), but understand that this method will amplify negative reactions as much as positive and so is inherently risky.