Apple's stock is already priced to account for their war chest. If the war chest is drawn down, the stock would (presumably) reflect this and drop in proportion to the amount of cash that's released.
That is true, however it is not why the/a stock market is irrational.
Well, first off, one person asked, the other told, but in your sentiment:
What you refer to is more likely a skew of information, a mix of information traders and (e.g.) value traders, or (generalizing term) noise traders.
There may not be a facit as to "Is this good or bad for the value of AAPL to have dividends paid out in this amount?". There may be different interpretations. Some might feel it's a sign of a new path in dividends payout from Apple even in the future. Some might think it's a short term "stunt" to keep the investors happy. Some might think it makes them less valuable as they have less money, some might think a strategy of catering to profit and investors will outweigh the "loss" in dividend payout.
Just looking at this thread of comments shows there are many interpretations.
