I'd go even further, and say that GitHub is incredibly well-known within their target market (developers). Everyone else doesn't matter, as the business will not be built around the general public.
WSJ is supposed to provide good reporting with strong bias towards informing potential investors (as a financial/business news paper). The wording choice doesn't make a strong case for value associated with the company and sounds like some no-name co. just got a pile of money that they are like to lose. (An exaggeration on my part for illustration purposes only.)