I think you'll find that a lot of websites don't use "hard black" (#000000). There's a perception that hard black text on a hard white background is the most legible combo, but in practice this can actually appear a bit harsh to some.

Even on non-Retina devices, as long as contrast isn't weakened too much, lightening the text can result in a softer, more appealing reading experience. (See most the way most "read later/readability" services format articles).