Everyone should know that the requirements in job listings are almost always guidelines, not a strict checklist. Obviously someone with 3 years of programming experience won’t be considered for this job, but someone who has 11 years of experience instead of the 12 listed in the requirements section should apply.
Rule of thumb: If you can reasonably say that you’re “close enough” to the listed requirements or you satisfy most but maybe not all of them, apply anyway. Let the company decide. Don’t waste your time applying to jobs you’re obviously not qualified for, but don’t prematurely reject yourself from jobs if you’re close enough.
Hiring is hard. Finding candidates is hard. Contrary to some of the more cynical comments on HN, hiring managers aren’t interested in rejecting otherwise qualified candidates due to small technicalities. That’s what Carmack is trying to convey here.