Do any of the comments actually make that conclusion? The other comment you replied to is the only one I saw that even comes close, but it mentions "if you can offer office hours..." so the poster clearly knew the "office hours" idiom.
I came into the comments section to see what this article is all about and whether I want to read it, thinking it would be about working on open source projects only 9 am to 5 pm. So this comment helped me a lot, and I'm voting it up so that it may stay on top.
Oh, don't get me wrong, I definitely think it's helpful to explain the idiom for those not familiar. I just found the description "a lot of the comments..." rather weird when I didn't see any.