Traders have no interest in clarifying false beliefs. If you think about it, you'll see that the stolen coins were probably sold *before* it became obvious they were stolen. Why would mybitcoin sell AFTER everybody tries to track their coins?
Also, this is a financial crash's bust pattern. Why would a sell-off from one or two thieves cause fancy spikes and saw-teeth?
I think people who blame stolen bitcoins or a guy running bots for the falling value are clutching at some very short straws.
17,000 bitcoins were allegedly stolen (mybitcoin says everything is back, btw), and that's meant to cause a crash in a market of almost 7 million? It doesn't seem very logical.
One guy running bots to corner the market? Maybe if he has several hundred thousand bitcoins to play with, otherwise that doesn't make sense either.
The only logical reasons for the falling value are the current state of the world economy (can't pay investment losses or taxes in bitcoins), panic (price is falling, which makes others sell before it hits zero), and the usefulness of bitcoins in the real world (currently, not very useful).
Sometimes a cigar is just a cigar.