Self publishing discrimination

Discrimination in a big way.
Why is is that big competitions do not allow self published novels? SP writers are locked out of all the big ones on the grounds that if you SP then it must be crap.
They only take published books from Publishing houses. As if they are the sole arbitration on taste. From the Premier's literary awards, The Bollinger PG Wodehouse humorous fiction,  and more. Shouldn't SP authors be afforded the same consideration as those who are 'picked up' by a house.


Thoughts.  
Please add to the list of competitions that discriminate. We need to shake the tree on Self Publishing.
http://www.ourbookclub.net.au/Prizewinners.php
http://nationalmirroronline.net/arts_culture/arts_culture_news/24548.html
http://www.tribalblogs.com/2011/09/07/from-kindle-selfpublishing-to-nobel-prize-in-literature-10-steps-to-literary-fame-%E2%80%93-a-very-personal-vademecum/
http://publishingperspectives.com/2011/07/how-long-before-self-published-book-wins-award/