In particular the sRAW does not contain information from the blue photosites in isolation, without interpolation or other contribution from the non-blue sites.An uncompressed RAW / NEF file contains 14-bits of data per filtered pixel, so color and luminance information is demosaiced by software to form RGB pixel data. When you open a RAW file in Camera RAW or Lightroom, the software reconstructs the image in color by using a demosaicing algorithm on the bayer pattern. An sRAW file is already demosaiced and reconstructed by manufacturer’s camera firmware, so it does not contain most of the information from the RAW file.
That particular article is talking about Nikon sRAW, but it seems that the description also applies to Canon's sRAW. See section 3.2, starting on page 10, of http://dougkerr.net/Pumpkin/articles/sRaw.pdf .