You're on a tangent. The point wasn't whether or not RSA is patentable (it was patented, obviously, though it was released to the public and would have expired by now anyway). It's that even among people ("experts in the field", legally) who understand modular exponentiation and can implement RSA correctly, the discovery of public key encryption represents a sublime moment of brilliance. I certainly never would have seen it, nor do I know anyone who claims they would have. Your point was that this kind of certainty didn't exist, and thus you're wrong (or else you're actually claiming that you think RSA was an obvious innovation, in which case let me compose myself before continuing...)

Even to someone (Hi!) who thinks all software patents are bad, RSA is patentable if anything is patentable. Slide to unlock, not even remotely so.