Why going back a few hundred years? Even a few decades ago the idea of patenting mathematics was still mostly considered absurd.
Imagine a world where people like e.g. Dijkstra and Lamport patented all their concurrency algorithms. Hoare patented quicksort. And so on.
It looks to my like it's a process to be carried out in hardware which is patented, and not the mathematics in question. It's a physical apparatus.
Even if it was purely mathematics, I think I would rather have someone patent it if possible and make it freely available than to leave it out and have someone else take a stab at patenting it, have the underfunded patent office fail to realize there is prior art, and grant the patent. Sure, you could effectively fight it, but until the system gets reformed enough to prevent most these abused, that's a lot of wasted resources (and having the patent lets them threaten others with it without actually bringing a case that could invalidate it).
