In what way? Maybe you have a different definition of human, but as one myself, and someone who produces lots of PDFs for others, it's absolutely readable. Double-click, open, read. Ultimately though the readability depends on the producer of the file...
I think you don't understand what "human-readable format" means. The Wikipedia article has a good overview[1]. Open any PDF in a text editor instead of a PDF viewer and you'll see why it's not a human-readable format.
