I haven't owned any shares of Yahoo! for years so my response to the comment "but greed had them" isn't a personal defense but an observation.
When Microsoft came knocking Jerry Yang wasn't telling shareholders to "be irrational", i.e. greedy. He was telling shareholders that there was greater value tied up in the Yahoo brand than Microsoft was offering.
IF investing is a manifestation of greed then everyone is guilty. However, most folks I know who are invested in the stock market aren't motivated by greed. They're motivated by reason, however poorly informed, by the likes of fiduciaries such as Jerry Yang.