[icebraining]

if there were a proper protocol for passing environment to subprocesses, that protocol would make a distinction between the two.

TCP is a binary protocol, how does it distinguish between executable and plain text formats? Answer: it doesn't, because TCP doesn't know or care about that, that's left to the layers above to handle.

Likewise, environment variables don't know or care about "functions", that's a concept that doesn't enter into the protocol, since it's not a shell specific protocol. All it transmits are keys and values, which are generic blobs of data. That bash uses the protocol to transmit code mixed up with data is no more the protocol's fault than the fact that TCP was used to transmit those same functions on HTTP requests.