Obviously reality slaps them in the face almost always and then they are shocked and in disbelief how their "perfect math isn't working, no this cannot be!".
The point is that hypothetically there is a way to make an extremal black hole, if you had essentially god-like powers. None of the authors are shocked or in disbelief that about this actually being possible.
In general mathematicians fall into two rough categories. Some are pure mathematicians who are happy doing their theoretical stuff and don't care whatsoever about what happens in reality. Others are more applied, and are usually very explicit about how and where their work matches and diverges from reality.
Probably someday someone will do it, but I don't think it's an incredibly interesting thing to do.
While 4 spin (1/2) particles could either act like a particle with spin 2, or like a particle with spin 1 (in one of three different ways) or like a particle with spin 0 (5 + 3*3 + 1 = 2^4 ) right?
So, what if we consider helium-4 nuclei in the spin 0 state?
Maybe that doesn’t make sense..
Just an aside: I think this is an oft-repeated misconception. It’s not so much that pure mathematicians ‘don’t care about reality’ — it’s more that they consider the mathematics itself to be reality already. If mathematics isn’t reality, I’m not sure what is.
As soon as you’re doing any kind of ‘modelling’, it would be reasonable to say it’s no longer ‘pure’ mathematics. Of course, the divide between pure and applied is somewhat fuzzy.