Why would you think "rich people made money"? They already hold the shares and would be trying to sell. It would be impossible to sell any large amount of shares after hours directly after a huge negative issue. If you could sell (say $1 million worth), it would be at a much lower price.
That's probably why the price dropped. The market doesn't actually react to news, it reacts to investors buying and selling. If the price went down that means people with lots of shares are trying to get out.
The funny thing is, a lot of these mush-brained first movers actually make a lot of money just by being first. They are bought out by a load of second or third place investors who end up holding the bag.
The later investors see the success of the first movers and try to replicate it, but without knowing what they are buying. At least the first investors usually know it's speculative. When they sell to later investors the company magically becomes "established", and is valued as if it will continue growing forever.
Nothing grows forever.