The thing that makes someone an expert in infosec or cryptography is not a certification, or special training, or a phrenological explanation of IQ, or whatever. You can find examples of security and cryptography minded people in all fields without any one thing except: engagement with the subject matter like it matters.
This is why I think I'm so angry at the world of cryptography with its "never do anything but what we tell you" strategy. This is not how you get people to engage with the material in a thoughtful and safe way.
And as time has gone on, this results in a growing crisis.