Agreed! If I were a founder and learned that someone in HR was using such arbitrary judgement, they'd be the one looking for a new job. By their standard they wouldn't hire someone like Fabrice Bellard: https://bellard.org/

Why not? Seems like he coded his personal website himself without an existing template.

Exactly. His accomplishments aside, that's the type of personal website that says "I don't really do web design, but I still made a page" --- obviously if you're hiring a web developer then plain nonstyled HTML would be a bit surprising, but someone in a non-web position showing such a site would definitely be seen positively: It indicates honesty and modesty.