Because nobody believes this feature request will ever be implemented.
Gox is a business not a no profit org.
Were I to be the most honest exchanger in the world I still would not release such information.
Because it attracts people with ill intentions for my business.
Mtgox's profit derives from the volume of trades, not from high prices. How that info can lower their volumes? Currently they have a problem with a trust. No information -> people getting out of Mtgox to bitstamp. Opening the queue info could only lead to building trust with their customers. So it is definitly in their interest to open queue info.