If the implementation done in less than an hour is not featureful enough for you, obviously you don't have to use it. Doesn't reflect the value in this type of post on HN.
If it was insufficiently pedagogical, or failed to give people the impression that shells are just software and They Can Do It Too, then I would understand the critique more, as those are clearly the goals.
I was trying to notify readers that the description is rather inaccurate; The HN title claims “Bourne-style shell”, and the article claims “shell in the style of the Bourne shell, Bash, zsh, etc.”, but a working shell actually requires TTY and signal handling; they’re not really optional features.
Sure, if all you’re doing is implementing a program with a command line interface like ftp(1), kermit(1), sftp(1), etc. that do not run arbitrary subprocesses, and do not need to handle being arbitrarily interrupted, then sure, implement away. I would suggest the Python “cmd” library as a good way to get started quickly. But for a login shell, used to run other programs, there are more complex considerations.
If it was insufficiently pedagogical, or failed to give people the impression that shells are just software and They Can Do It Too, then I would understand the critique more, as those are clearly the goals.