Because people here thought it was interesting. Is there a better reason?

Or maybe some people have been on projects where someone else butchered their code really badly and appreciate the parallel?

Yes: better would be interesting AND relevant to HN.

These reminders are a good thing.

If people with accounts at HN vote it up, isn't it de facto relevant?

No. Because of the huge influx of new people who are used to general purpose versions of HN.