I’ve spent nearly twenty years blogging, giving talks and releasing open source code. [...] I’ve interviewed hundreds of people [...] The vast majority of candidates have little to no evidence of creativity in public at all Are we sure the author is not showing some unconscious bias by looking in others for traits he has (public creativity)? There is no particular reason why public creativity is linked to good engine…
He never claimed it means you're a good engineer. It's advice for standing out among other applicants when you're looking for a job.