Removing that using chrome's inspector made this text legible again.
What?
What he means is that the contrast between the text and background makes the article hard to read. If they would up the font-weight to 400 from 300 it would give a much better contrast.
Huh, I didn't even notice it. I wonder if this is due to text rendering differences between platforms? The page is pretty readable on Safari on OS X.
Any time you see mid- or light-grey text on white, you know that the designer is on OSX and doesn't care one jot about other viewers.
They may care, but they're simply unaware of how bad it looks, and also unaware of browsershots.org and similar services :)
It's a bit light in Safari on OS X on a non-Retina screen.