If not those shareholders may also want to exit shortly after the IPO, creating a success story for the IPO should increase demand creating a better market for shareholders.
I do agree with you that in a market with rational agents and solely from the POV of Facebook, Inc. that they did the best thing, but I think in a market filled with irrational agents motivated primarily by price movements that it creates the wrong story for the next 3 to 6 months in the overall social context.
What they've created is dinner conversation about how Facebook is flopping and has provided lots of ammunition to the nay-sayers, rather than 'proving' the nay-sayers wrong.
I tend to see Facebook's business fundamentally as hype, people use it because other people use it, not because of some intrinsic thing that makes it better than any other social network. It's moat is it's userbase not it's technology.
It's like Coca-Cola, people drink Coke because other people drink coke, not because it tastes better than Pepsi. It's the fundamental reason why New Coke was a flop and Pepsi taste tests don't matter.
The attitude expressed in your comment is really disturbing.
It seems like people are investing in what other people will be willing to buy this otherwise useless stock at, and those people are only willing to do it because of yet other people willing to buy it for the same reason. Is that not correct? Seems like an extremely bizarre form of "investment", it's betting on a horse, not owning a portion of a horse.
On the other hand, if they sell the stock to the public at $38 and it drops down to $34, it's someone else that's out the $4. Sure, it may create some temporary negative publicity, but, as you stated, they will recover.