The author only used rot13 to make a point about the failure mode of inspection. DPI is only there to stop everyday employees from bypassing security policies inadvertently, not to stop an actual attacker. An attacker could use any number of other approaches: hiding payloads in innocuous keywords, using actual encryption, steganography, what have you.

I'm not a security expert but we had those kind of measures at a previous job and AFAIK they are there so that a lazy employee (me) doesn't just skip configuring their tools to go through Artifactory out of laziness and introduce a supply chain vulnerability. If "pip install XYZ" just worked out of the box, how likely would it be that all 10k devs in your organization would bother configuring it to avoid PYPI?