The reason we tell people not to implement their own crypto is that no matter how skilled someone is, no matter what language they program in, it is nearly cert

The reason we tell people not to implement their own crypto is that no matter how skilled someone is, no matter what language they program in, it is nearly certain that self-rolled crypto code will have security flaws. Cryptographic security hinges on key, subtle assumptions that are very easy to screw up. World famous cryptographers do not roll their own crypto (except for research code). When people do implement cryptography they rely on having large numbers of other people review it. That is not a model that scales to having a large number (more than a couple dozen) of competing implementations.