Clearly Maxwell's laws would take the form of a series of hard and fast rules that cheese makers must abide by if they want truly radiant cheeses that brighten up the day of whomever imbibes in them!
Over and over, I find myself turning to Brandon Sanderson's First Rule of Magic.
Sanderson’s First Law of Magics: An author’s ability to solve conflict with magic is DIRECTLY PROPORTIONAL to how well the reader understands said magic.
Sanderson originally phrased it with respect to magic, but I find it to be a powerful general purpose tool which has great applications in science fiction scenarios as well. The only difference is how we understand magic or science. One is expected to understand the magic on their own, while with science we readily accept the words of the "grey beards" who tell us from on high the rules of science. Why do we accept this? It's a survival trait in this world. Science has gone so far beyond what the average person can understand that they have no choice but to accept it on faith.
Accordingly, the first step I would have with such impossible to work through worldbuilding exercises is to rephrase it in terms of Sanderson's law. The particular exercise they are exploring has a purpose. They're trying to sell a story, or grapple with some other idea in their head, or any number of reasons for the exercise to pop into being. The writer needs to be given a chance to come to an understanding of what they are actually trying to do. Without such an understanding, it will be hard to explain to them why they should stop wanting the impossible.
After that, for many literary scenarios, Sanderson's law can be brought into play. For many scenarios, the purpose is to either solve conflict or create conflict, both of which are covered by Sanderson's blog regarding his laws. Suggest that a modified version of Sanderson's law is valid in this scenario, such as "An author's ability to create enjoyable worlds with the adjustment of equations is DIRECTLY PROPORTIONAL to how well the reader understands said equations." In general, many of these kinds of questions involve a writer that doesn't really understand the equations themselves, so this becomes a very valid argument: how can you depend on your readers to understand that which you do not?
In the case of the linked question, the assumption appears to be that reality is dictated by the equations, not the other way around. The real need of the writer is described in the words: "...so as something would move very quickly, it would appear to be harder to accelerate, but there would be no cosmic speed limit..." that described the actual need for their world, rather than simply the equation. From there, one can start to tug at the question of why the author is exploring such a world and what they intend to get out of it. Maybe then, a magic like effect can be put in play.
On the other hand, Maxwell's laws may refer to something about the proper etiquette when consuming cheese and coffee at the same table. After all, Maxwell's House is owned by Kraft, and J.L. Kraft started his empire on a cheese business.